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<div class="book" data-level="1.3" data-chapter-title="査找重復的行" data-filepath="ch1/ch1-03.md" data-basepath=".." data-revision="Wed Dec 09 2015 15:54:13 GMT+0800 (中国标准时间)">
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前言
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<li class="chapter " data-level="0.1" data-path="ch0/ch0-01.html">
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<b>0.1.</b>
Go語言起源
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<li class="chapter " data-level="0.2" data-path="ch0/ch0-02.html">
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<b>0.2.</b>
Go語言項目
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<li class="chapter " data-level="0.3" data-path="ch0/ch0-03.html">
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<b>0.3.</b>
本書的組織
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<b>0.4.</b>
更多的信息
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<b>0.5.</b>
緻謝
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<li class="chapter " data-level="1" data-path="ch1/ch1.html">
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<b>1.</b>
入門
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<li class="chapter " data-level="1.1" data-path="ch1/ch1-01.html">
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<b>1.1.</b>
Hello, World
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<li class="chapter " data-level="1.2" data-path="ch1/ch1-02.html">
<a href="../ch1/ch1-02.html">
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<b>1.2.</b>
命令行參數
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<li class="chapter active" data-level="1.3" data-path="ch1/ch1-03.html">
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<b>1.3.</b>
査找重復的行
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<li class="chapter " data-level="1.4" data-path="ch1/ch1-04.html">
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<b>1.4.</b>
GIF動畫
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<li class="chapter " data-level="1.5" data-path="ch1/ch1-05.html">
<a href="../ch1/ch1-05.html">
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<b>1.5.</b>
穫取URL
</a>
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<li class="chapter " data-level="1.6" data-path="ch1/ch1-06.html">
<a href="../ch1/ch1-06.html">
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<b>1.6.</b>
併髮穫取多個URL
</a>
</li>
<li class="chapter " data-level="1.7" data-path="ch1/ch1-07.html">
<a href="../ch1/ch1-07.html">
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<b>1.7.</b>
Web服務
</a>
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<li class="chapter " data-level="1.8" data-path="ch1/ch1-08.html">
<a href="../ch1/ch1-08.html">
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<b>1.8.</b>
本章要點
</a>
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</ul>
</li>
<li class="chapter " data-level="2" data-path="ch2/ch2.html">
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<b>2.</b>
程序結構
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<li class="chapter " data-level="2.1" data-path="ch2/ch2-01.html">
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<b>2.1.</b>
命名
</a>
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<li class="chapter " data-level="2.2" data-path="ch2/ch2-02.html">
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<b>2.2.</b>
聲明
</a>
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<li class="chapter " data-level="2.3" data-path="ch2/ch2-03.html">
<a href="../ch2/ch2-03.html">
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<b>2.3.</b>
變量
</a>
</li>
<li class="chapter " data-level="2.4" data-path="ch2/ch2-04.html">
<a href="../ch2/ch2-04.html">
<i class="fa fa-check"></i>
<b>2.4.</b>
賦值
</a>
</li>
<li class="chapter " data-level="2.5" data-path="ch2/ch2-05.html">
<a href="../ch2/ch2-05.html">
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<b>2.5.</b>
類型
</a>
</li>
<li class="chapter " data-level="2.6" data-path="ch2/ch2-06.html">
<a href="../ch2/ch2-06.html">
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<b>2.6.</b>
包和文件
</a>
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<li class="chapter " data-level="2.7" data-path="ch2/ch2-07.html">
<a href="../ch2/ch2-07.html">
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<b>2.7.</b>
作用域
</a>
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</ul>
</li>
<li class="chapter " data-level="3" data-path="ch3/ch3.html">
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<b>3.</b>
基礎數據類型
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<li class="chapter " data-level="3.1" data-path="ch3/ch3-01.html">
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<b>3.1.</b>
整型
</a>
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<li class="chapter " data-level="3.2" data-path="ch3/ch3-02.html">
<a href="../ch3/ch3-02.html">
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<b>3.2.</b>
浮點數
</a>
</li>
<li class="chapter " data-level="3.3" data-path="ch3/ch3-03.html">
<a href="../ch3/ch3-03.html">
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<b>3.3.</b>
復數
</a>
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<li class="chapter " data-level="3.4" data-path="ch3/ch3-04.html">
<a href="../ch3/ch3-04.html">
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<b>3.4.</b>
佈爾型
</a>
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<li class="chapter " data-level="3.5" data-path="ch3/ch3-05.html">
<a href="../ch3/ch3-05.html">
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<b>3.5.</b>
字符串
</a>
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<li class="chapter " data-level="3.6" data-path="ch3/ch3-06.html">
<a href="../ch3/ch3-06.html">
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<b>3.6.</b>
常量
</a>
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</ul>
</li>
<li class="chapter " data-level="4" data-path="ch4/ch4.html">
<a href="../ch4/ch4.html">
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<b>4.</b>
復閤數據類型
</a>
<ul class="articles">
<li class="chapter " data-level="4.1" data-path="ch4/ch4-01.html">
<a href="../ch4/ch4-01.html">
<i class="fa fa-check"></i>
<b>4.1.</b>
數組
</a>
</li>
<li class="chapter " data-level="4.2" data-path="ch4/ch4-02.html">
<a href="../ch4/ch4-02.html">
<i class="fa fa-check"></i>
<b>4.2.</b>
切片
</a>
</li>
<li class="chapter " data-level="4.3" data-path="ch4/ch4-03.html">
<a href="../ch4/ch4-03.html">
<i class="fa fa-check"></i>
<b>4.3.</b>
字典
</a>
</li>
<li class="chapter " data-level="4.4" data-path="ch4/ch4-04.html">
<a href="../ch4/ch4-04.html">
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<b>4.4.</b>
結構體
</a>
</li>
<li class="chapter " data-level="4.5" data-path="ch4/ch4-05.html">
<a href="../ch4/ch4-05.html">
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<b>4.5.</b>
JSON
</a>
</li>
<li class="chapter " data-level="4.6" data-path="ch4/ch4-06.html">
<a href="../ch4/ch4-06.html">
<i class="fa fa-check"></i>
<b>4.6.</b>
文本和HTML模闆
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="5" data-path="ch5/ch5.html">
<a href="../ch5/ch5.html">
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<b>5.</b>
函數
</a>
<ul class="articles">
<li class="chapter " data-level="5.1" data-path="ch5/ch5-01.html">
<a href="../ch5/ch5-01.html">
<i class="fa fa-check"></i>
<b>5.1.</b>
函數聲明
</a>
</li>
<li class="chapter " data-level="5.2" data-path="ch5/ch5-02.html">
<a href="../ch5/ch5-02.html">
<i class="fa fa-check"></i>
<b>5.2.</b>
遞歸
</a>
</li>
<li class="chapter " data-level="5.3" data-path="ch5/ch5-03.html">
<a href="../ch5/ch5-03.html">
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<b>5.3.</b>
多返迴值
</a>
</li>
<li class="chapter " data-level="5.4" data-path="ch5/ch5-04.html">
<a href="../ch5/ch5-04.html">
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<b>5.4.</b>
錯誤
</a>
</li>
<li class="chapter " data-level="5.5" data-path="ch5/ch5-05.html">
<a href="../ch5/ch5-05.html">
<i class="fa fa-check"></i>
<b>5.5.</b>
函數值
</a>
</li>
<li class="chapter " data-level="5.6" data-path="ch5/ch5-06.html">
<a href="../ch5/ch5-06.html">
<i class="fa fa-check"></i>
<b>5.6.</b>
匿名函數
</a>
</li>
<li class="chapter " data-level="5.7" data-path="ch5/ch5-07.html">
<a href="../ch5/ch5-07.html">
<i class="fa fa-check"></i>
<b>5.7.</b>
可變參數
</a>
</li>
<li class="chapter " data-level="5.8" data-path="ch5/ch5-08.html">
<a href="../ch5/ch5-08.html">
<i class="fa fa-check"></i>
<b>5.8.</b>
Deferred函數
</a>
</li>
<li class="chapter " data-level="5.9" data-path="ch5/ch5-09.html">
<a href="../ch5/ch5-09.html">
<i class="fa fa-check"></i>
<b>5.9.</b>
Panic異常
</a>
</li>
<li class="chapter " data-level="5.10" data-path="ch5/ch5-10.html">
<a href="../ch5/ch5-10.html">
<i class="fa fa-check"></i>
<b>5.10.</b>
Recover捕穫異常
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="6" data-path="ch6/ch6.html">
<a href="../ch6/ch6.html">
<i class="fa fa-check"></i>
<b>6.</b>
方法
</a>
<ul class="articles">
<li class="chapter " data-level="6.1" data-path="ch6/ch6-01.html">
<a href="../ch6/ch6-01.html">
<i class="fa fa-check"></i>
<b>6.1.</b>
方法聲明
</a>
</li>
<li class="chapter " data-level="6.2" data-path="ch6/ch6-02.html">
<a href="../ch6/ch6-02.html">
<i class="fa fa-check"></i>
<b>6.2.</b>
基於指鍼對象的方法
</a>
</li>
<li class="chapter " data-level="6.3" data-path="ch6/ch6-03.html">
<a href="../ch6/ch6-03.html">
<i class="fa fa-check"></i>
<b>6.3.</b>
通過嵌入結構體來擴展類型
</a>
</li>
<li class="chapter " data-level="6.4" data-path="ch6/ch6-04.html">
<a href="../ch6/ch6-04.html">
<i class="fa fa-check"></i>
<b>6.4.</b>
方法值和方法錶達式
</a>
</li>
<li class="chapter " data-level="6.5" data-path="ch6/ch6-05.html">
<a href="../ch6/ch6-05.html">
<i class="fa fa-check"></i>
<b>6.5.</b>
示例: Bit數組
</a>
</li>
<li class="chapter " data-level="6.6" data-path="ch6/ch6-06.html">
<a href="../ch6/ch6-06.html">
<i class="fa fa-check"></i>
<b>6.6.</b>
封裝
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="7" data-path="ch7/ch7.html">
<a href="../ch7/ch7.html">
<i class="fa fa-check"></i>
<b>7.</b>
接口
</a>
<ul class="articles">
<li class="chapter " data-level="7.1" data-path="ch7/ch7-01.html">
<a href="../ch7/ch7-01.html">
<i class="fa fa-check"></i>
<b>7.1.</b>
接口是閤約
</a>
</li>
<li class="chapter " data-level="7.2" data-path="ch7/ch7-02.html">
<a href="../ch7/ch7-02.html">
<i class="fa fa-check"></i>
<b>7.2.</b>
接口類型
</a>
</li>
<li class="chapter " data-level="7.3" data-path="ch7/ch7-03.html">
<a href="../ch7/ch7-03.html">
<i class="fa fa-check"></i>
<b>7.3.</b>
實現接口的條件
</a>
</li>
<li class="chapter " data-level="7.4" data-path="ch7/ch7-04.html">
<a href="../ch7/ch7-04.html">
<i class="fa fa-check"></i>
<b>7.4.</b>
flag.Value接口
</a>
</li>
<li class="chapter " data-level="7.5" data-path="ch7/ch7-05.html">
<a href="../ch7/ch7-05.html">
<i class="fa fa-check"></i>
<b>7.5.</b>
接口值
</a>
</li>
<li class="chapter " data-level="7.6" data-path="ch7/ch7-06.html">
<a href="../ch7/ch7-06.html">
<i class="fa fa-check"></i>
<b>7.6.</b>
sort.Interface接口
</a>
</li>
<li class="chapter " data-level="7.7" data-path="ch7/ch7-07.html">
<a href="../ch7/ch7-07.html">
<i class="fa fa-check"></i>
<b>7.7.</b>
http.Handler接口
</a>
</li>
<li class="chapter " data-level="7.8" data-path="ch7/ch7-08.html">
<a href="../ch7/ch7-08.html">
<i class="fa fa-check"></i>
<b>7.8.</b>
error接口
</a>
</li>
<li class="chapter " data-level="7.9" data-path="ch7/ch7-09.html">
<a href="../ch7/ch7-09.html">
<i class="fa fa-check"></i>
<b>7.9.</b>
示例: 錶達式求值
</a>
</li>
<li class="chapter " data-level="7.10" data-path="ch7/ch7-10.html">
<a href="../ch7/ch7-10.html">
<i class="fa fa-check"></i>
<b>7.10.</b>
類型斷言
</a>
</li>
<li class="chapter " data-level="7.11" data-path="ch7/ch7-11.html">
<a href="../ch7/ch7-11.html">
<i class="fa fa-check"></i>
<b>7.11.</b>
基於類型斷言識彆錯誤類型
</a>
</li>
<li class="chapter " data-level="7.12" data-path="ch7/ch7-12.html">
<a href="../ch7/ch7-12.html">
<i class="fa fa-check"></i>
<b>7.12.</b>
通過類型斷言査詢接口
</a>
</li>
<li class="chapter " data-level="7.13" data-path="ch7/ch7-13.html">
<a href="../ch7/ch7-13.html">
<i class="fa fa-check"></i>
<b>7.13.</b>
類型分支
</a>
</li>
<li class="chapter " data-level="7.14" data-path="ch7/ch7-14.html">
<a href="../ch7/ch7-14.html">
<i class="fa fa-check"></i>
<b>7.14.</b>
示例: 基於標記的XML解碼
</a>
</li>
<li class="chapter " data-level="7.15" data-path="ch7/ch7-15.html">
<a href="../ch7/ch7-15.html">
<i class="fa fa-check"></i>
<b>7.15.</b>
補充幾點
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="8" data-path="ch8/ch8.html">
<a href="../ch8/ch8.html">
<i class="fa fa-check"></i>
<b>8.</b>
Goroutines和Channels
</a>
<ul class="articles">
<li class="chapter " data-level="8.1" data-path="ch8/ch8-01.html">
<a href="../ch8/ch8-01.html">
<i class="fa fa-check"></i>
<b>8.1.</b>
Goroutines
</a>
</li>
<li class="chapter " data-level="8.2" data-path="ch8/ch8-02.html">
<a href="../ch8/ch8-02.html">
<i class="fa fa-check"></i>
<b>8.2.</b>
示例: 併髮的Clock服務
</a>
</li>
<li class="chapter " data-level="8.3" data-path="ch8/ch8-03.html">
<a href="../ch8/ch8-03.html">
<i class="fa fa-check"></i>
<b>8.3.</b>
示例: 併髮的Echo服務
</a>
</li>
<li class="chapter " data-level="8.4" data-path="ch8/ch8-04.html">
<a href="../ch8/ch8-04.html">
<i class="fa fa-check"></i>
<b>8.4.</b>
Channels
</a>
</li>
<li class="chapter " data-level="8.5" data-path="ch8/ch8-05.html">
<a href="../ch8/ch8-05.html">
<i class="fa fa-check"></i>
<b>8.5.</b>
併行的循環
</a>
</li>
<li class="chapter " data-level="8.6" data-path="ch8/ch8-06.html">
<a href="../ch8/ch8-06.html">
<i class="fa fa-check"></i>
<b>8.6.</b>
示例: 併髮的Web爬蟲
</a>
</li>
<li class="chapter " data-level="8.7" data-path="ch8/ch8-07.html">
<a href="../ch8/ch8-07.html">
<i class="fa fa-check"></i>
<b>8.7.</b>
基於select的多路復用
</a>
</li>
<li class="chapter " data-level="8.8" data-path="ch8/ch8-08.html">
<a href="../ch8/ch8-08.html">
<i class="fa fa-check"></i>
<b>8.8.</b>
示例: 併髮的字典遍歷
</a>
</li>
<li class="chapter " data-level="8.9" data-path="ch8/ch8-09.html">
<a href="../ch8/ch8-09.html">
<i class="fa fa-check"></i>
<b>8.9.</b>
併髮的退齣
</a>
</li>
<li class="chapter " data-level="8.10" data-path="ch8/ch8-10.html">
<a href="../ch8/ch8-10.html">
<i class="fa fa-check"></i>
<b>8.10.</b>
示例: 聊天服務
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="9" data-path="ch9/ch9.html">
<a href="../ch9/ch9.html">
<i class="fa fa-check"></i>
<b>9.</b>
基於共享變量的併髮
</a>
<ul class="articles">
<li class="chapter " data-level="9.1" data-path="ch9/ch9-01.html">
<a href="../ch9/ch9-01.html">
<i class="fa fa-check"></i>
<b>9.1.</b>
競爭條件
</a>
</li>
<li class="chapter " data-level="9.2" data-path="ch9/ch9-02.html">
<a href="../ch9/ch9-02.html">
<i class="fa fa-check"></i>
<b>9.2.</b>
sync.Mutex互斥鎖
</a>
</li>
<li class="chapter " data-level="9.3" data-path="ch9/ch9-03.html">
<a href="../ch9/ch9-03.html">
<i class="fa fa-check"></i>
<b>9.3.</b>
sync.RWMutex讀寫鎖
</a>
</li>
<li class="chapter " data-level="9.4" data-path="ch9/ch9-04.html">
<a href="../ch9/ch9-04.html">
<i class="fa fa-check"></i>
<b>9.4.</b>
內存衕步
</a>
</li>
<li class="chapter " data-level="9.5" data-path="ch9/ch9-05.html">
<a href="../ch9/ch9-05.html">
<i class="fa fa-check"></i>
<b>9.5.</b>
sync.Once初始化
</a>
</li>
<li class="chapter " data-level="9.6" data-path="ch9/ch9-06.html">
<a href="../ch9/ch9-06.html">
<i class="fa fa-check"></i>
<b>9.6.</b>
競爭條件檢測
</a>
</li>
<li class="chapter " data-level="9.7" data-path="ch9/ch9-07.html">
<a href="../ch9/ch9-07.html">
<i class="fa fa-check"></i>
<b>9.7.</b>
示例: 併髮的非阻塞緩存
</a>
</li>
<li class="chapter " data-level="9.8" data-path="ch9/ch9-08.html">
<a href="../ch9/ch9-08.html">
<i class="fa fa-check"></i>
<b>9.8.</b>
Goroutines和綫程
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="10" data-path="ch10/ch10.html">
<a href="../ch10/ch10.html">
<i class="fa fa-check"></i>
<b>10.</b>
包和工具
</a>
<ul class="articles">
<li class="chapter " data-level="10.1" data-path="ch10/ch10-01.html">
<a href="../ch10/ch10-01.html">
<i class="fa fa-check"></i>
<b>10.1.</b>
簡介
</a>
</li>
<li class="chapter " data-level="10.2" data-path="ch10/ch10-02.html">
<a href="../ch10/ch10-02.html">
<i class="fa fa-check"></i>
<b>10.2.</b>
導入路徑
</a>
</li>
<li class="chapter " data-level="10.3" data-path="ch10/ch10-03.html">
<a href="../ch10/ch10-03.html">
<i class="fa fa-check"></i>
<b>10.3.</b>
包聲明
</a>
</li>
<li class="chapter " data-level="10.4" data-path="ch10/ch10-04.html">
<a href="../ch10/ch10-04.html">
<i class="fa fa-check"></i>
<b>10.4.</b>
導入聲明
</a>
</li>
<li class="chapter " data-level="10.5" data-path="ch10/ch10-05.html">
<a href="../ch10/ch10-05.html">
<i class="fa fa-check"></i>
<b>10.5.</b>
匿名導入
</a>
</li>
<li class="chapter " data-level="10.6" data-path="ch10/ch10-06.html">
<a href="../ch10/ch10-06.html">
<i class="fa fa-check"></i>
<b>10.6.</b>
包和命名
</a>
</li>
<li class="chapter " data-level="10.7" data-path="ch10/ch10-07.html">
<a href="../ch10/ch10-07.html">
<i class="fa fa-check"></i>
<b>10.7.</b>
工具
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="11" data-path="ch11/ch11.html">
<a href="../ch11/ch11.html">
<i class="fa fa-check"></i>
<b>11.</b>
測試
</a>
<ul class="articles">
<li class="chapter " data-level="11.1" data-path="ch11/ch11-01.html">
<a href="../ch11/ch11-01.html">
<i class="fa fa-check"></i>
<b>11.1.</b>
go test
</a>
</li>
<li class="chapter " data-level="11.2" data-path="ch11/ch11-02.html">
<a href="../ch11/ch11-02.html">
<i class="fa fa-check"></i>
<b>11.2.</b>
測試函數
</a>
</li>
<li class="chapter " data-level="11.3" data-path="ch11/ch11-03.html">
<a href="../ch11/ch11-03.html">
<i class="fa fa-check"></i>
<b>11.3.</b>
測試覆蓋率
</a>
</li>
<li class="chapter " data-level="11.4" data-path="ch11/ch11-04.html">
<a href="../ch11/ch11-04.html">
<i class="fa fa-check"></i>
<b>11.4.</b>
基準測試
</a>
</li>
<li class="chapter " data-level="11.5" data-path="ch11/ch11-05.html">
<a href="../ch11/ch11-05.html">
<i class="fa fa-check"></i>
<b>11.5.</b>
剖析
</a>
</li>
<li class="chapter " data-level="11.6" data-path="ch11/ch11-06.html">
<a href="../ch11/ch11-06.html">
<i class="fa fa-check"></i>
<b>11.6.</b>
示例函數
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="12" data-path="ch12/ch12.html">
<a href="../ch12/ch12.html">
<i class="fa fa-check"></i>
<b>12.</b>
反射
</a>
<ul class="articles">
<li class="chapter " data-level="12.1" data-path="ch12/ch12-01.html">
<a href="../ch12/ch12-01.html">
<i class="fa fa-check"></i>
<b>12.1.</b>
為何需要反射?
</a>
</li>
<li class="chapter " data-level="12.2" data-path="ch12/ch12-02.html">
<a href="../ch12/ch12-02.html">
<i class="fa fa-check"></i>
<b>12.2.</b>
reflect.Type和reflect.Value
</a>
</li>
<li class="chapter " data-level="12.3" data-path="ch12/ch12-03.html">
<a href="../ch12/ch12-03.html">
<i class="fa fa-check"></i>
<b>12.3.</b>
Display遞歸打印
</a>
</li>
<li class="chapter " data-level="12.4" data-path="ch12/ch12-04.html">
<a href="../ch12/ch12-04.html">
<i class="fa fa-check"></i>
<b>12.4.</b>
示例: 編碼S錶達式
</a>
</li>
<li class="chapter " data-level="12.5" data-path="ch12/ch12-05.html">
<a href="../ch12/ch12-05.html">
<i class="fa fa-check"></i>
<b>12.5.</b>
通過reflect.Value脩改值
</a>
</li>
<li class="chapter " data-level="12.6" data-path="ch12/ch12-06.html">
<a href="../ch12/ch12-06.html">
<i class="fa fa-check"></i>
<b>12.6.</b>
示例: 解碼S錶達式
</a>
</li>
<li class="chapter " data-level="12.7" data-path="ch12/ch12-07.html">
<a href="../ch12/ch12-07.html">
<i class="fa fa-check"></i>
<b>12.7.</b>
穫取結構體字段標識
</a>
</li>
<li class="chapter " data-level="12.8" data-path="ch12/ch12-08.html">
<a href="../ch12/ch12-08.html">
<i class="fa fa-check"></i>
<b>12.8.</b>
顯示一個類型的方法集
</a>
</li>
<li class="chapter " data-level="12.9" data-path="ch12/ch12-09.html">
<a href="../ch12/ch12-09.html">
<i class="fa fa-check"></i>
<b>12.9.</b>
幾點忠告
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="13" data-path="ch13/ch13.html">
<a href="../ch13/ch13.html">
<i class="fa fa-check"></i>
<b>13.</b>
底層編程
</a>
<ul class="articles">
<li class="chapter " data-level="13.1" data-path="ch13/ch13-01.html">
<a href="../ch13/ch13-01.html">
<i class="fa fa-check"></i>
<b>13.1.</b>
unsafe.Sizeof, Alignof 和 Offsetof
</a>
</li>
<li class="chapter " data-level="13.2" data-path="ch13/ch13-02.html">
<a href="../ch13/ch13-02.html">
<i class="fa fa-check"></i>
<b>13.2.</b>
unsafe.Pointer
</a>
</li>
<li class="chapter " data-level="13.3" data-path="ch13/ch13-03.html">
<a href="../ch13/ch13-03.html">
<i class="fa fa-check"></i>
<b>13.3.</b>
示例: 深度相等判斷
</a>
</li>
<li class="chapter " data-level="13.4" data-path="ch13/ch13-04.html">
<a href="../ch13/ch13-04.html">
<i class="fa fa-check"></i>
<b>13.4.</b>
通過cgo調用C代碼
</a>
</li>
<li class="chapter " data-level="13.5" data-path="ch13/ch13-05.html">
<a href="../ch13/ch13-05.html">
<i class="fa fa-check"></i>
<b>13.5.</b>
幾點忠告
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="14" data-path="exercise/ex.html">
<a href="../exercise/ex.html">
<i class="fa fa-check"></i>
<b>14.</b>
習題解答
</a>
<ul class="articles">
<li class="chapter " data-level="14.1" data-path="exercise/ex-ch1.html">
<a href="../exercise/ex-ch1.html">
<i class="fa fa-check"></i>
<b>14.1.</b>
第一章 入門
</a>
</li>
</ul>
</li>
<li class="chapter " data-level="15" data-path="errata.html">
<a href="../errata.html">
<i class="fa fa-check"></i>
<b>15.</b>
勘誤
</a>
</li>
<li class="divider"></li>
<li>
<a href="https://www.gitbook.com" target="blank" class="gitbook-link">
本書使用 GitBook 釋出
</a>
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<a href="../" >Go编程语言</a>
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<section class="normal" id="section-">
<h2 id="13-&#x67FB;&#x627E;&#x91CD;&#x5FA9;&#x7684;&#x884C;">1.3. &#x67FB;&#x627E;&#x91CD;&#x5FA9;&#x7684;&#x884C;</h2>
<p>&#x6587;&#x4EF6;&#x62F7;&#x8C9D;&#x3001;&#x6587;&#x4EF6;&#x6253;&#x5370;&#x3001;&#x6587;&#x4EF6;&#x8490;&#x7D22;&#x3001;&#x6587;&#x4EF6;&#x6392;&#x5E8F;&#x3001;&#x6587;&#x4EF6;&#x7D71;&#x8A08;&#x985E;&#x7684;&#x7A0B;&#x5E8F;&#x4E00;&#x822C;&#x90FD;&#x6703;&#x6709;&#x6BD4;&#x8F03;&#x76F8;&#x4F3C;&#x7684;&#x7A0B;&#x5E8F;&#x7D50;&#x69CB;&#xFF1A;&#x8655;&#x7406;&#x8F38;&#x5165;&#x7684;&#x4E00;&#x500B;&#x5FAA;&#x74B0;&#xFF0C;&#x5728;&#x6BCF;&#x4E00;&#x500B;&#x8F38;&#x5165;&#x5143;&#x7D20;&#x4E0A;&#x57F7;&#x884C;&#x8A08;&#x7B97;&#x8655;&#x7406;&#xFF0C;&#x5728;&#x8655;&#x7406;&#x7684;&#x8855;&#x6642;&#x6216;&#x8005;&#x8655;&#x7406;&#x5B8C;&#x6210;&#x4E4B;&#x5F8C;&#x9032;&#x884C;&#x7D50;&#x679C;&#x8F38;&#x9F63;&#x3002;&#x6211;&#x5011;&#x6703;&#x5C55;&#x793A;&#x4E00;&#x500B;&#x53EB;dup&#x7A0B;&#x5E8F;&#x7684;&#x4E09;&#x500B;&#x7248;&#x672C;&#xFF1B;&#x9019;&#x500B;&#x7A0B;&#x5E8F;&#x7684;&#x9748;&#x611F;&#x4F86;&#x81EA;&#x65BC;linux&#x7684;uniq&#x547D;&#x4EE4;&#xFF0C;&#x6211;&#x5011;&#x7684;&#x7A0B;&#x5E8F;&#x5C07;&#x6703;&#x627E;&#x5230;&#x76F8;&#x9130;&#x7684;&#x91CD;&#x5FA9;&#x7684;&#x884C;&#x3002;&#x9019;&#x500B;&#x7A0B;&#x5E8F;&#x63D0;&#x4F9B;&#x7684;&#x6A21;&#x5F0F;&#x53EF;&#x4EE5;&#x5F88;&#x65B9;&#x4FBF;&#x5730;&#x88AB;&#x8129;&#x6539;&#x4F86;&#x5B8C;&#x6210;&#x4E0D;&#x8855;&#x7684;&#x9700;&#x6C42;&#x3002;</p>
<p>&#x7B2C;&#x4E00;&#x500B;&#x7248;&#x672C;&#x7684;dup&#x6703;&#x8F38;&#x9F63;&#x6A19;&#x6E96;&#x8F38;&#x5165;&#x6D41;&#x4E2D;&#x7684;&#x9F63;&#x73FE;&#x591A;&#x6B21;&#x7684;&#x884C;&#xFF0C;&#x5728;&#x884C;&#x5167;&#x5BB9;&#x524D;&#x6703;&#x6709;&#x5176;&#x9F63;&#x73FE;&#x6B21;&#x6578;&#x7684;&#x8A08;&#x6578;&#x3002;&#x9019;&#x500B;&#x7A0B;&#x5E8F;&#x5C07;&#x5F15;&#x5165;if&#x9336;&#x9054;&#x5F0F;&#xFF0C;map&#x5167;&#x7F6E;&#x6578;&#x64DA;&#x7D50;&#x679C;&#x548C;bufio&#x7684;package&#x3002;</p>
<pre><code class="lang-go">gopl.io/ch1/dup1
<span class="hljs-comment">// Dup1 prints the text of each line that appears more than</span>
<span class="hljs-comment">// once in the standard input, preceded by its count.</span>
<span class="hljs-keyword">package</span> main
<span class="hljs-keyword">import</span> (
<span class="hljs-string">&quot;bufio&quot;</span>
<span class="hljs-string">&quot;fmt&quot;</span>
<span class="hljs-string">&quot;os&quot;</span>
)
<span class="hljs-keyword">func</span> main() {
counts := <span class="hljs-built_in">make</span>(<span class="hljs-keyword">map</span>[<span class="hljs-typename">string</span>]<span class="hljs-typename">int</span>)
input := bufio.NewScanner(os.Stdin)
<span class="hljs-keyword">for</span> input.Scan() {
counts[input.Text()]++
}
<span class="hljs-comment">// <span class="hljs-doctag">NOTE:</span> ignoring potential errors from input.Err()</span>
<span class="hljs-keyword">for</span> line, n := <span class="hljs-keyword">range</span> counts {
<span class="hljs-keyword">if</span> n &gt; <span class="hljs-number">1</span> {
fmt.Printf(<span class="hljs-string">&quot;%d\t%s\n&quot;</span>, n, line)
}
}
}
</code></pre>
<p>&#x548C;&#x6211;&#x5011;&#x524D;&#x9EAB;&#x63D0;&#x5230;&#x7684;for&#x5FAA;&#x74B0;&#x4E00;&#x6A23;&#xFF0C;&#x5728;if&#x689D;&#x4EF6;&#x7684;&#x5169;&#x908A;&#xFF0C;&#x6211;&#x5011;&#x4E5F;&#x4E0D;&#x9700;&#x8981;&#x52A0;&#x62EC;&#x865F;&#xFF0C;&#x4F46;&#x662F;if&#x9336;&#x9054;&#x5F0F;&#x5F8C;&#x7684;&#x908F;&#x8F2F;&#x9AD4;&#x7684;&#x82B1;&#x62EC;&#x865F;&#x662F;&#x4E0D;&#x80FD;&#x7701;&#x7565;&#x7684;&#x3002;&#x5982;&#x679C;&#x9700;&#x8981;&#x7684;&#x8A71;&#xFF0C;&#x50CF;&#x5176;&#x5B83;&#x8A9E;&#x8A00;&#x4E00;&#x6A23;&#xFF0C;&#x9019;&#x500B;&#x9336;&#x9054;&#x5F0F;&#x4E5F;&#x53EF;&#x4EE5;&#x6709;else&#x90E8;&#x5206;&#xFF0C;&#x9019;&#x90E8;&#x5206;&#x908F;&#x8F2F;&#x6703;&#x5728;if&#x4E2D;&#x7684;&#x689D;&#x4EF6;&#x7D50;&#x679C;&#x70BA;false&#x6642;&#x88AB;&#x57F7;&#x884C;&#x3002;</p>
<p>map&#x662F;go&#x8A9E;&#x8A00;&#x5167;&#x7F6E;&#x7684;key/value&#x6578;&#x64DA;&#x7D50;&#x69CB;&#xFF0C;&#x9019;&#x500B;&#x6578;&#x64DA;&#x7D50;&#x69CB;&#x80FD;&#x5920;&#x63D0;&#x4F9B;&#x5E38;&#x6578;&#x6642;&#x9593;&#x7684;&#x5B58;&#x5132;&#x3001;&#x7A6B;&#x53D6;&#x3001;&#x6E2C;&#x8A66;&#x64CD;&#x4F5C;&#x3002;key&#x53EF;&#x4EE5;&#x662F;&#x4EFB;&#x610F;&#x6578;&#x64DA;&#x985E;&#x578B;&#xFF0C;&#x96BB;&#x8981;&#x8A72;&#x985E;&#x578B;&#x80FD;&#x5920;&#x7528;==&#x4F86;&#x9032;&#x884C;&#x6BD4;&#x8F03;&#xFF0C;string&#x662F;&#x6700;&#x5E38;&#x7528;&#x7684;key&#x985E;&#x578B;&#x3002;&#x800C;value&#x985E;&#x578B;&#x7684;&#x7BC4;&#x570D;&#x5C31;&#x66F4;&#x5927;&#x4E86;&#xFF0C;&#x57FA;&#x672C;&#x4E0A;&#x4EC0;&#x9EBC;&#x985E;&#x578B;&#x90FD;&#x662F;&#x53EF;&#x4EE5;&#x7684;&#x3002;&#x9019;&#x500B;&#x4F8B;&#x5B50;&#x4E2D;&#x7684;key&#x90FD;&#x662F;string&#x985E;&#x578B;&#xFF0C;value&#x7528;&#x7684;&#x662F;int&#x985E;&#x578B;&#x3002;&#x6211;&#x5011;&#x7528;&#x5167;&#x7F6E;make&#x51FD;&#x6578;&#x4F86;&#x5275;&#x5EFA;&#x4E00;&#x500B;&#x7A7A;&#x7684;map&#xFF0C;&#x7576;&#x7136;&#x4E86;&#xFF0C;make&#x65B9;&#x6CD5;&#x9084;&#x53EF;&#x4EE5;&#x6709;&#x5F46;&#x7684;&#x7528;&#x8655;&#x3002;&#x5728;4.3&#x7AE0;&#x4E2D;&#x6211;&#x5011;&#x9084;&#x6703;&#x5C0D;map&#x9032;&#x884C;&#x66F4;&#x6DF1;&#x5EA6;&#x7684;&#x8A0E;&#x8AD6;&#x3002;</p>
<p>dup&#x7A0B;&#x5E8F;&#x6BCF;&#x6B21;&#x8B80;&#x53D6;&#x8F38;&#x5165;&#x7684;&#x4E00;&#x884C;&#xFF0C;&#x9019;&#x4E00;&#x884C;&#x7684;&#x5167;&#x5BB9;&#x6703;&#x88AB;&#x7576;&#x505A;&#x4E00;&#x500B;map&#x7684;key&#xFF0C;&#x800C;&#x5176;value&#x503C;&#x6703;&#x88AB;+1&#x3002;counts[input.Text()]++&#x9019;&#x500B;&#x8A9E;&#x53E5;&#x548C;&#x4E0B;&#x9EAB;&#x7684;&#x5169;&#x53E5;&#x662F;&#x7B49;&#x50F9;&#x7684;&#xFF1A;</p>
<pre><code class="lang-go">line := input.Text()
counts[line] = counts[line] + <span class="hljs-number">1</span>
</code></pre>
<p>&#x7576;&#x7136;&#x4E86;&#xFF0C;&#x5728;&#x9019;&#x500B;&#x4F8B;&#x5B50;&#x88CF;&#x6211;&#x5011;&#x4F75;&#x4E0D;&#x7528;&#x64D4;&#x5FC3;map&#x5728;&#x6C92;&#x6709;&#x7576;&#x524D;&#x7684;key&#x6642;&#x5C31;&#x5C0D;&#x5176;&#x9032;&#x884C;++&#x64CD;&#x4F5C;&#x6703;&#x6709;&#x4EC0;&#x9EBC;&#x554F;&#x984C;&#xFF0C;&#x56E0;&#x70BA;go&#x8A9E;&#x8A00;&#x5728;&#x78B0;&#x5230;&#x9019;&#x7A2E;&#x60C5;&#x6CC1;&#x6642;&#xFF0C;&#x6703;&#x81EA;&#x52D5;&#x5C07;&#x5176;&#x521D;&#x59CB;&#x5316;&#x70BA;0&#xFF0C;&#x7136;&#x5F8C;&#x518D;&#x9032;&#x884C;&#x64CD;&#x4F5C;&#x3002;</p>
<p>&#x5728;&#x9019;&#x88CF;&#x6211;&#x5011;&#x53C8;&#x7528;&#x4E86;&#x4E00;&#x500B;range&#x7684;&#x5FAA;&#x74B0;&#x4F86;&#x6253;&#x5370;&#x7D50;&#x679C;&#xFF0C;&#x9019;&#x6B21;range&#x662F;&#x88AB;&#x7528;&#x5728;map&#x9019;&#x500B;&#x6578;&#x64DA;&#x7D50;&#x679C;&#x4E0A;&#x3002;&#x9019;&#x4E00;&#x6B21;&#x7684;&#x60C5;&#x6CC1;&#x548C;&#x4E0A;&#x6B21;&#x6BD4;&#x8F03;&#x985E;&#x578B;&#xFF0C;range&#x6703;&#x8FD4;&#x8FF4;&#x5169;&#x500B;&#x503C;&#xFF0C;&#x4E00;&#x500B;key&#x548C;&#x5728;map&#x5C0D;&#x61C9;&#x9019;&#x500B;key&#x7684;value&#x3002;&#x5C0D;map&#x9032;&#x884C;range&#x5FAA;&#x74B0;&#x6642;&#xFF0C;&#x5176;&#x9806;&#x5E8F;&#x662F;&#x4E0D;&#x78BA;&#x5B9A;&#x7684;&#xFF0C;&#x5F9E;&#x5BE6;&#x8E10;&#x4F86;&#x770B;&#xFF0C;&#x5F88;&#x53EF;&#x80FD;&#x6BCF;&#x6B21;&#x904B;&#x884C;&#x90FD;&#x6703;&#x6709;&#x4E0D;&#x4E00;&#x6A23;&#x7684;&#x7D50;&#x679C;(&#x8B6F;&#x8A3B;&#xFF1A;&#x9019;&#x662F;go&#x7684;&#x8A2D;&#x8A08;&#x8005;&#x6709;&#x610F;&#x70BA;&#x4E4B;&#x7684;&#xFF0C;&#x56E0;&#x70BA;&#x5176;&#x5E95;&#x5C64;&#x5BE6;&#x73FE;&#x4E0D;&#x4FDD;&#x8B49;&#x63D2;&#x5165;&#x9806;&#x5E8F;&#x548C;&#x904D;&#x6B77;&#x9806;&#x5E8F;&#x4E00;&#x7DFB;&#xFF0C;&#x800C;&#x5E0C;&#x671B;&#x7A0B;&#x5E8F;&#x54E1;&#x4E0D;&#x8981;&#x4F9D;&#x8CF4;&#x904D;&#x6B77;&#x6642;&#x7684;&#x9806;&#x5E8F;&#xFF0C;&#x6240;&#x4EE5;&#x5E79;&#x8106;&#x76F4;&#x63A5;&#x5728;&#x904D;&#x6B77;&#x7684;&#x6642;&#x5019;&#x505A;&#x4E86;&#x96A8;&#x6A5F;&#x5316;&#x8655;&#x7406;&#xFF0C;&#x9189;&#x4E86;)&#xFF0C;&#x4F86;&#x907F;&#x514D;&#x7A0B;&#x5E8F;&#x54E1;&#x5728;&#x696D;&#x52D9;&#x4E2D;&#x4F9D;&#x8CF4;&#x904D;&#x6B77;&#x6642;&#x7684;&#x9806;&#x5E8F;&#x3002;</p>
<p>&#x7136;&#x5F8C;&#x8F2A;&#x5230;&#x6211;&#x5011;&#x4F8B;&#x5B50;&#x4E2D;&#x7684;bufio&#x9019;&#x500B;package&#x4E86;&#xFF0C;&#x9019;&#x500B;package&#x4E3B;&#x8981;&#x7684;&#x76EE;&#x7684;&#x662F;&#x5E6B;&#x52A9;&#x6211;&#x5011;&#x66F4;&#x65B9;&#x4FBF;&#x6709;&#x6548;&#x5730;&#x8655;&#x7406;&#x7A0B;&#x5E8F;&#x7684;&#x8F38;&#x5165;&#x548C;&#x8F38;&#x9F63;&#x3002;&#x800C;&#x9019;&#x500B;&#x5305;&#x6700;&#x6709;&#x7528;&#x7684;&#x4E00;&#x500B;&#x7279;&#x6027;&#x5C31;&#x662F;&#x5176;&#x4E2D;&#x7684;&#x4E00;&#x500B;Scanner&#x985E;&#x578B;&#xFF0C;&#x7528;&#x5B83;&#x53EF;&#x4EE5;&#x7C21;&#x55AE;&#x5730;&#x63A5;&#x6536;&#x8F38;&#x5165;&#xFF0C;&#x6216;&#x8005;&#x628A;&#x8F38;&#x5165;&#x6253;&#x6563;&#x6210;&#x884C;&#x6216;&#x8005;&#x55AE;&#x8A5E;&#xFF1B;&#x9019;&#x500B;&#x985E;&#x578B;&#x901A;&#x5E38;&#x662F;&#x8655;&#x7406;&#x884C;&#x5F62;&#x5F0F;&#x7684;&#x8F38;&#x5165;&#x6700;&#x7C21;&#x55AE;&#x7684;&#x65B9;&#x6CD5;&#x4E86;&#x3002;</p>
<p>&#x672C;&#x7A0B;&#x5E8F;&#x4E2D;&#x7528;&#x4E86;&#x4E00;&#x500B;&#x77ED;&#x8B8A;&#x91CF;&#x8072;&#x660E;&#xFF0C;&#x4F86;&#x5275;&#x5EFA;&#x4E00;&#x500B;buffio.Scanner&#x5C0D;&#x8C61;&#xFF1A;</p>
<pre><code>input := bufio.NewScanner(os.Stdin)
</code></pre><p>scanner&#x5C0D;&#x8C61;&#x53EF;&#x4EE5;&#x5F9E;&#x7A0B;&#x5E8F;&#x7684;&#x6A19;&#x6E96;&#x8F38;&#x5165;&#x4E2D;&#x8B80;&#x53D6;&#x5167;&#x5BB9;&#x3002;&#x5C0D;input.Scanner&#x7684;&#x6BCF;&#x4E00;&#x6B21;&#x8ABF;&#x7528;&#x90FD;&#x6703;&#x8ABF;&#x5165;&#x4E00;&#x500B;&#x65B0;&#x884C;&#xFF0C;&#x4F75;&#x4E14;&#x6703;&#x81EA;&#x52D5;&#x5C07;&#x5176;&#x884C;&#x672B;&#x7684;&#x63DB;&#x884C;&#x7B26;&#x53BB;&#x6389;&#xFF1B;&#x5176;&#x7D50;&#x679C;&#x53EF;&#x4EE5;&#x7528;input.Text()&#x5F97;&#x5230;&#x3002;Scan&#x65B9;&#x6CD5;&#x5728;&#x8B80;&#x5230;&#x4E86;&#x65B0;&#x884C;&#x7684;&#x6642;&#x5019;&#x6703;&#x8FD4;&#x8FF4;true&#xFF0C;&#x800C;&#x5728;&#x6C92;&#x6709;&#x65B0;&#x884C;&#x88AB;&#x8B80;&#x5165;&#x6642;&#xFF0C;&#x6703;&#x8FD4;&#x8FF4;false&#x3002;</p>
<p>&#x4F8B;&#x5B50;&#x4E2D;&#x9084;&#x6709;&#x4E00;&#x500B;fmt.Printf&#xFF0C;&#x9019;&#x500B;&#x51FD;&#x6578;&#x548C;C&#x7E6B;&#x7684;&#x5176;&#x5B83;&#x8A9E;&#x8A00;&#x88CF;&#x7684;&#x90A3;&#x500B;printf&#x51FD;&#x6578;&#x5DEE;&#x4E0D;&#x591A;&#xFF0C;&#x90FD;&#x662F;&#x683C;&#x5F0F;&#x5316;&#x8F38;&#x9F63;&#x7684;&#x65B9;&#x6CD5;&#x3002;fmt.Printf&#x7684;&#x7B2C;&#x4E00;&#x500B;&#x53C3;&#x6578;&#x537D;&#x662F;&#x8F38;&#x9F63;&#x5167;&#x5BB9;&#x7684;&#x683C;&#x5F0F;&#x898F;&#x7D04;&#xFF0C;&#x6BCF;&#x4E00;&#x500B;&#x53C3;&#x6578;&#x5982;&#x679C;&#x683C;&#x5F0F;&#x5316;&#x662F;&#x53D6;&#x6C7A;&#x65BC;&#x5728;&#x683C;&#x5F0F;&#x5316;&#x5B57;&#x7B26;&#x4E32;&#x88CF;&#x9F63;&#x73FE;&#x7684;&#x201C;&#x8F49;&#x63DB;&#x5B57;&#x7B26;&#x201D;&#xFF0C;&#x9019;&#x500B;&#x5B57;&#x7B26;&#x4E32;&#x662F;&#x8DDF;&#x7740;%&#x865F;&#x5F8C;&#x7684;&#x4E00;&#x500B;&#x5B57;&#x6BCD;&#x3002;&#x6BD4;&#x5982;%d&#x9336;&#x793A;&#x4EE5;&#x4E00;&#x500B;&#x6574;&#x6578;&#x7684;&#x5F62;&#x5F0F;&#x4F86;&#x6253;&#x5370;&#x4E00;&#x500B;&#x8B8A;&#x91CF;&#xFF0C;&#x800C;%s&#xFF0C;&#x5247;&#x9336;&#x793A;&#x4EE5;string&#x5F62;&#x5F0F;&#x4F86;&#x6253;&#x5370;&#x4E00;&#x500B;&#x8B8A;&#x91CF;&#x3002;</p>
<p>Printf&#x6709;&#x4E00;&#x5927;&#x5806;&#x9019;&#x7A2E;&#x8F49;&#x63DB;&#xFF0C;Go&#x7A0B;&#x5E8F;&#x54E1;&#x628A;&#x9019;&#x4E9B;&#x53EB;&#x505A;verb(&#x52D5;&#x8A5E;)&#x3002;&#x4E0B;&#x9EAB;&#x7684;&#x9336;&#x683C;&#x5217;&#x9F63;&#x4E86;&#x5E38;&#x7528;&#x7684;&#x52D5;&#x8A5E;&#xFF0C;&#x7576;&#x7136;&#x4E86;&#x4E0D;&#x662F;&#x5168;&#x90E8;&#xFF0C;&#x4F46;&#x57FA;&#x672C;&#x4E5F;&#x5920;&#x7528;&#x4E86;&#x3002;</p>
<pre><code>%d int&#x8B8A;&#x91CF;
%x, %o, %b &#x5206;&#x5F46;&#x70BA;16&#x9032;&#x88FD;&#xFF0C;8&#x9032;&#x88FD;&#xFF0C;2&#x9032;&#x88FD;&#x5F62;&#x5F0F;&#x7684;int
%f, %g, %e &#x6D6E;&#x9EDE;&#x6578;&#xFF1A; 3.141593 3.141592653589793 3.141593e+00
%t &#x4F48;&#x723E;&#x8B8A;&#x91CF;&#xFF1A;true &#x6216; false
%c rune (Unicode code point)&#xFF0C;go&#x8A9E;&#x8A00;&#x88CF;&#x7279;&#x6709;&#x7684;Unicode&#x5B57;&#x7B26;&#x985E;&#x578B;
%s string
%q quoted string &quot;abc&quot; or rune &apos;c&apos;
%v &#x6703;&#x5C07;&#x4EFB;&#x610F;&#x8B8A;&#x91CF;&#x4EE5;&#x6613;&#x8B80;&#x7684;&#x5F62;&#x5F0F;&#x6253;&#x5370;&#x9F63;&#x4F86;
%T &#x6253;&#x5370;&#x8B8A;&#x91CF;&#x7684;&#x985E;&#x578B;
%% &#x5B57;&#x7B26;&#x578B;&#x767E;&#x5206;&#x6BD4;&#x6A19;&#x8A8C;(&#x4E0D;&#x78BA;&#x5B9A;) literal percent sign (no operand)
</code></pre><p>dup1&#x4E2D;&#x7684;&#x7A0B;&#x5E8F;&#x9084;&#x5305;&#x542B;&#x4E86;&#x4E00;&#x500B;\t&#x548C;\n&#x7684;&#x683C;&#x5F0F;&#x5316;&#x5B57;&#x7B26;&#x4E32;&#x3002;&#x5728;&#x5B57;&#x7B26;&#x4E32;&#x4E2D;&#x6703;&#x4EE5;&#x9019;&#x4E9B;&#x7279;&#x6B8A;&#x7684;&#x8F49;&#x7FA9;&#x5B57;&#x7B26;&#x4F86;&#x9336;&#x793A;&#x4E0D;&#x53EF;&#x898B;&#x5B57;&#x7B26;&#x3002;Printf&#x9ED8;&#x8A8D;&#x4E0D;&#x6703;&#x5728;&#x8F38;&#x9F63;&#x5167;&#x5BB9;&#x5F8C;&#x52A0;&#x4E0A;&#x63DB;&#x884C;&#x7B26;&#x3002;&#x6309;&#x7167;&#x6163;&#x4F8B;&#xFF0C;&#x7528;&#x4F86;&#x683C;&#x5F0F;&#x5316;&#x7684;&#x51FD;&#x6578;&#x90FD;&#x6703;&#x5728;&#x672B;&#x5C3E;&#x4EE5;f&#x5B57;&#x6BCD;&#x7D50;&#x5C3E;&#xFF0C;&#x6BD4;&#x5982;log.Printf&#xFF0C;fmt.Errorf&#xFF0C;&#x8855;&#x6642;&#x9084;&#x6709;&#x4E00;&#x7E6B;&#x5217;&#x5C0D;&#x61C9;&#x4EE5;ln&#x7D50;&#x5C3E;&#x7684;&#x51FD;&#x6578;&#xFF0C;&#x9019;&#x4E9B;&#x51FD;&#x6578;&#x9ED8;&#x8A8D;&#x4EE5;%v&#x4F86;&#x683C;&#x5F0F;&#x5316;&#x4ED6;&#x5011;&#x7684;&#x53C3;&#x6578;&#xFF0C;&#x4F75;&#x4E14;&#x6703;&#x5728;&#x8F38;&#x9F63;&#x7D50;&#x675F;&#x5F8C;&#x5728;&#x6700;&#x5F8C;&#x81EA;&#x52D5;&#x52A0;&#x4E0A;&#x4E00;&#x500B;&#x63DB;&#x884C;&#x7B26;&#x3002;</p>
<p>&#x8A31;&#x591A;&#x7A0B;&#x5E8F;&#x5F9E;&#x6A19;&#x6E96;&#x8F38;&#x5165;&#x4E2D;&#x8B80;&#x53D6;&#x6578;&#x64DA;&#xFF0C;&#x50CF;&#x4E0A;&#x9EAB;&#x7684;&#x4F8B;&#x5B50;&#x90A3;&#x6A23;&#x3002;&#x9664;&#x6B64;&#x4E4B;&#x5916;&#xFF0C;&#x9084;&#x53EF;&#x80FD;&#x5F9E;&#x4E00;&#x7E6B;&#x5217;&#x7684;&#x6587;&#x4EF6;&#x4E2D;&#x8B80;&#x53D6;&#x3002;&#x4E0B;&#x4E00;&#x500B;dup&#x7A0B;&#x5E8F;&#x5C31;&#x662F;&#x5F9E;&#x6A19;&#x6E96;&#x8F38;&#x5165;&#x4E2D;&#x8B80;&#x5230;&#x4E00;&#x4E9B;&#x6587;&#x4EF6;&#x540D;&#xFF0C;&#x7528;os.Open&#x51FD;&#x6578;&#x4F86;&#x6253;&#x958B;&#x6BCF;&#x4E00;&#x500B;&#x6587;&#x4EF6;&#x7A6B;&#x53D6;&#x5167;&#x5BB9;&#x7684;&#x3002;</p>
<pre><code class="lang-go">gopl.io/ch1/dup2
<span class="hljs-comment">// Dup2 prints the count and text of lines that appear more than once</span>
<span class="hljs-comment">// in the input. It reads from stdin or from a list of named files.</span>
<span class="hljs-keyword">package</span> main
<span class="hljs-keyword">import</span> (
<span class="hljs-string">&quot;bufio&quot;</span>
<span class="hljs-string">&quot;fmt&quot;</span>
<span class="hljs-string">&quot;os&quot;</span>
)
<span class="hljs-keyword">func</span> main() {
counts := <span class="hljs-built_in">make</span>(<span class="hljs-keyword">map</span>[<span class="hljs-typename">string</span>]<span class="hljs-typename">int</span>)
files := os.Args[<span class="hljs-number">1</span>:]
<span class="hljs-keyword">if</span> <span class="hljs-built_in">len</span>(files) == <span class="hljs-number">0</span> {
countLines(os.Stdin, counts)
} <span class="hljs-keyword">else</span> {
<span class="hljs-keyword">for</span> _, arg := <span class="hljs-keyword">range</span> files {
f, err := os.Open(arg)
<span class="hljs-keyword">if</span> err != <span class="hljs-constant">nil</span> {
fmt.Fprintf(os.Stderr, <span class="hljs-string">&quot;dup2: %v\n&quot;</span>, err)
<span class="hljs-keyword">continue</span>
}
countLines(f, counts)
f.Close()
}
}
<span class="hljs-keyword">for</span> line, n := <span class="hljs-keyword">range</span> counts {
<span class="hljs-keyword">if</span> n &gt; <span class="hljs-number">1</span> {
fmt.Printf(<span class="hljs-string">&quot;%d\t%s\n&quot;</span>, n, line)
}
}
}
<span class="hljs-keyword">func</span> countLines(f *os.File, counts <span class="hljs-keyword">map</span>[<span class="hljs-typename">string</span>]<span class="hljs-typename">int</span>) {
input := bufio.NewScanner(f)
<span class="hljs-keyword">for</span> input.Scan() {
counts[input.Text()]++
}
<span class="hljs-comment">// <span class="hljs-doctag">NOTE:</span> ignoring potential errors from input.Err()</span>
}
</code></pre>
<p>os.Open&#x51FD;&#x6578;&#x6703;&#x8FD4;&#x8FF4;&#x5169;&#x500B;&#x503C;&#x3002;&#x7B2C;&#x4E00;&#x500B;&#x503C;&#x662F;&#x4E00;&#x500B;&#x6253;&#x958B;&#x7684;&#x6587;&#x4EF6;&#x985E;&#x578B;(*os.File)&#xFF0C;&#x9019;&#x500B;&#x5C0D;&#x8C61;&#x5728;&#x4E0B;&#x9EAB;&#x7684;&#x7A0B;&#x5E8F;&#x4E2D;&#x88AB;Scanner&#x8B80;&#x53D6;&#x3002;</p>
<p>os.Open&#x8FD4;&#x8FF4;&#x7684;&#x7B2C;&#x4E8C;&#x500B;&#x503C;&#x662F;&#x4E00;&#x500B;go&#x5167;&#x7F6E;&#x7684;error&#x985E;&#x578B;&#x3002;&#x5982;&#x679C;&#x9019;&#x500B;error&#x548C;&#x5167;&#x7F6E;&#x503C;&#x7684;nil(&#x8B6F;&#x8A3B;&#xFF1A;&#x76F8;&#x7576;&#x65BC;&#x5176;&#x5B83;&#x8A9E;&#x8A00;&#x88CF;&#x7684;NULL)&#x76F8;&#x7B49;&#x7684;&#x8A71;&#xFF0C;&#x8AAA;&#x660E;&#x6587;&#x4EF6;&#x88AB;&#x6210;&#x529F;&#x7684;&#x6253;&#x958B;&#x4E86;&#x3002;&#x4E4B;&#x5F8C;&#x6587;&#x4EF6;&#x88AB;&#x8B80;&#x53D6;&#xFF0C;&#x4E00;&#x76F4;&#x5230;&#x6587;&#x4EF6;&#x7684;&#x6700;&#x5F8C;&#xFF0C;Close&#x51FD;&#x6578;&#x95DC;&#x9589;&#x8A72;&#x6587;&#x4EF6;&#xFF0C;&#x4F75;&#x91CB;&#x653E;&#x76F8;&#x61C9;&#x7684;&#x4F54;&#x7528;&#x4E00;&#x5207;&#x8CC7;&#x6E90;&#x3002;&#x53E6;&#x4E00;&#x65B9;&#x9EAB;&#xFF0C;&#x5982;&#x679C;err&#x7684;&#x503C;&#x4E0D;&#x662F;nil&#x7684;&#x8A71;&#xFF0C;&#x90A3;&#x8AAA;&#x660E;&#x5728;&#x6253;&#x958B;&#x6587;&#x4EF6;&#x7684;&#x6642;&#x5019;&#x9F63;&#x4E86;&#x67D0;&#x7A2E;&#x932F;&#x8AA4;&#x3002;&#x9019;&#x7A2E;&#x60C5;&#x6CC1;&#x4E0B;&#xFF0C;error&#x985E;&#x578B;&#x7684;&#x503C;&#x6703;&#x63CF;&#x8FF0;&#x5177;&#x9AD4;&#x7684;&#x554F;&#x984C;&#x3002;&#x6211;&#x5011;&#x4F8B;&#x5B50;&#x88CF;&#x7684;&#x7C21;&#x55AE;&#x932F;&#x8AA4;&#x8655;&#x7406;&#x6703;&#x5728;&#x6A19;&#x6E96;&#x932F;&#x8AA4;&#x6D41;&#x4E2D;&#x7528;Fprintf&#x548C;%v&#x4F86;&#x683C;&#x5F0F;&#x5316;&#x8A72;&#x932F;&#x8AA4;&#x5B57;&#x7B26;&#x4E32;&#x3002;&#x7136;&#x5F8C;&#x7E7C;&#x7E8C;&#x8655;&#x7406;&#x4E0B;&#x4E00;&#x500B;&#x6587;&#x4EF6;&#xFF1B;continue&#x8A9E;&#x53E5;&#x6703;&#x76F4;&#x63A5;&#x8DF3;&#x904E;&#x4E4B;&#x5F8C;&#x7684;&#x8A9E;&#x53E5;&#xFF0C;&#x76F4;&#x63A5;&#x958B;&#x59CB;&#x57F7;&#x884C;&#x4E0B;&#x4E00;&#x6B21;&#x5FAA;&#x74B0;&#x3002;</p>
<p>&#x6211;&#x5011;&#x5728;&#x672C;&#x66F8;&#x4E2D;&#x65E9;&#x671F;&#x7684;&#x4F8B;&#x5B50;&#x4E2D;&#x505A;&#x4E86;&#x6BD4;&#x8F03;&#x8A73;&#x76E1;&#x7684;&#x932F;&#x8AA4;&#x8655;&#x7406;&#xFF0C;&#x7576;&#x7136;&#x4E86;&#xFF0C;&#x5728;&#x5BE6;&#x969B;&#x7DE8;&#x78BC;&#x904E;&#x7A0B;&#x4E2D;&#xFF0C;&#x50CF;os.Open&#x9019;&#x985E;&#x7684;&#x51FD;&#x6578;&#x662F;&#x4E00;&#x5B9A;&#x8981;&#x6AA2;&#x67FB;&#x5176;&#x8FD4;&#x8FF4;&#x7684;error&#x503C;&#x7684;&#xFF1B;&#x70BA;&#x4E86;&#x6E1B;&#x5C11;&#x4F8B;&#x5B50;&#x7A0B;&#x5E8F;&#x7684;&#x4EE3;&#x78BC;&#x91CF;&#xFF0C;&#x6211;&#x5011;&#x59D1;&#x4E14;&#x7C21;&#x5316;&#x6389;&#x9019;&#x4E9B;&#x4E0D;&#x592A;&#x53EF;&#x80FD;&#x8FD4;&#x8FF4;&#x932F;&#x8AA4;&#x7684;&#x908F;&#x8F2F;&#x3002;&#x5F8C;&#x9EAB;&#x7684;&#x4F8B;&#x5B50;&#x88CF;&#x6211;&#x5011;&#x6703;&#x8DF3;&#x904E;&#x932F;&#x8AA4;&#x6AA2;&#x67FB;&#x3002;&#x5728;5.4&#x7BC0;&#x4E2D;&#x6211;&#x5011;&#x6703;&#x5C0D;&#x932F;&#x8AA4;&#x8655;&#x7406;&#x505A;&#x66F4;&#x8A73;&#x7D30;&#x7684;&#x95E1;&#x8FF0;&#x3002;</p>
<p>&#x8B80;&#x8005;&#x53EF;&#x4EE5;&#x518D;&#x89C0;&#x5BDF;&#x4E00;&#x4E0B;&#x4E0A;&#x9EAB;&#x7684;&#x4F8B;&#x5B50;&#xFF0C;&#x6211;&#x5011;&#x7684;countLines&#x51FD;&#x6578;&#x662F;&#x5728;&#x5176;&#x8072;&#x660E;&#x4E4B;&#x524D;&#x5C31;&#x88AB;&#x8ABF;&#x7528;&#x4E86;&#x3002;&#x5728;Go&#x8A9E;&#x8A00;&#x88CF;&#xFF0C;&#x51FD;&#x6578;&#x548C;&#x5305;&#x7D1A;&#x5F46;&#x7684;&#x8B8A;&#x91CF;&#x53EF;&#x4EE5;&#x4EE5;&#x4EFB;&#x610F;&#x7684;&#x9806;&#x5E8F;&#x88AB;&#x8072;&#x660E;&#xFF0C;&#x4F75;&#x4E0D;&#x5F71;&#x97FF;&#x5176;&#x88AB;&#x8ABF;&#x7528;&#x3002;(&#x8B6F;&#x8A3B;&#xFF1A;&#x6700;&#x597D;&#x9084;&#x662F;&#x9075;&#x5FAA;&#x4E00;&#x5B9A;&#x7684;&#x898F;&#x7BC4;)</p>
<p>&#x518D;&#x4F86;&#x8B1B;&#x8B1B;map&#x9019;&#x500B;&#x6578;&#x64DA;&#x7D50;&#x69CB;&#xFF0C;map&#x662F;&#x7528;make&#x51FD;&#x6578;&#x5275;&#x5EFA;&#x7684;&#x6578;&#x64DA;&#x7D50;&#x69CB;&#x7684;&#x4E00;&#x500B;&#x5F15;&#x7528;&#x3002;&#x7576;&#x4E00;&#x500B;map&#x88AB;&#x4F5C;&#x70BA;&#x53C3;&#x6578;&#x50B3;&#x905E;&#x7D66;&#x4E00;&#x500B;&#x51FD;&#x6578;&#x6642;&#xFF0C;&#x51FD;&#x6578;&#x63A5;&#x6536;&#x5230;&#x7684;&#x662F;&#x4E00;&#x4EFD;&#x5F15;&#x7528;&#x7684;&#x62F7;&#x8C9D;&#xFF0C;&#x96D6;&#x7136;&#x672C;&#x8EAB;&#x4F75;&#x4E0D;&#x662F;&#x4E00;&#x500B;&#x6771;&#x897F;&#xFF0C;&#x4F46;&#x56E0;&#x70BA;&#x4ED6;&#x5011;&#x6307;&#x66CF;&#x7684;&#x662F;&#x8855;&#x4E00;&#x584A;&#x6578;&#x64DA;&#x5C0D;&#x8C61;(&#x8B6F;&#x8A3B;&#xFF1A;&#x985E;&#x4F3C;&#x65BC;C&#x8279;&#x88CF;&#x7684;&#x5F15;&#x7528;&#x50B3;&#x905E;)&#xFF0C;&#x6240;&#x4EE5;&#x4F60;&#x5728;&#x51FD;&#x6578;&#x88CF;&#x5C0D;map&#x88CF;&#x7684;&#x503C;&#x9032;&#x884C;&#x8129;&#x6539;&#x6642;&#xFF0C;&#x539F;&#x59CB;&#x7684;map&#x5167;&#x7684;&#x503C;&#x4E5F;&#x6703;&#x6539;&#x8B8A;&#x3002;&#x5728;&#x6211;&#x5011;&#x7684;&#x4F8B;&#x5B50;&#x4E2D;&#xFF0C;&#x6211;&#x5011;&#x5728;countLines&#x51FD;&#x6578;&#x4E2D;&#x63D2;&#x5165;&#x5230;counts&#x9019;&#x500B;map&#x88CF;&#x7684;&#x503C;&#xFF0C;&#x5728;&#x4E3B;&#x51FD;&#x6578;&#x4E2D;&#x4E5F;&#x662F;&#x770B;&#x5F97;&#x5230;&#x7684;&#x3002;</p>
<p>&#x4E0A;&#x9EAB;&#x9019;&#x500B;&#x7248;&#x672C;&#x7684;dup&#x662F;&#x4EE5;&#x6D41;&#x7684;&#x5F62;&#x5F0F;&#x4F86;&#x8655;&#x7406;&#x8F38;&#x5165;&#xFF0C;&#x4F75;&#x5C07;&#x5176;&#x6253;&#x6563;&#x70BA;&#x884C;&#x3002;&#x7406;&#x8AD6;&#x4E0A;&#x9019;&#x4E9B;&#x7A0B;&#x5E8F;&#x4E5F;&#x662F;&#x53EF;&#x4EE5;&#x4EE5;&#x4E8C;&#x9032;&#x88FD;&#x5F62;&#x5F0F;&#x4F86;&#x8655;&#x7406;&#x8F38;&#x5165;&#x7684;&#x3002;&#x6211;&#x5011;&#x4E5F;&#x53EF;&#x4EE5;&#x4E00;&#x6B21;&#x6027;&#x7684;&#x628A;&#x6574;&#x500B;&#x8F38;&#x5165;&#x5167;&#x5BB9;&#x5168;&#x90E8;&#x8B80;&#x5230;&#x5167;&#x5B58;&#x4E2D;&#xFF0C;&#x7136;&#x5F8C;&#x518D;&#x628A;&#x5176;&#x5206;&#x5272;&#x70BA;&#x591A;&#x884C;&#xFF0C;&#x7136;&#x5F8C;&#x518D;&#x53BB;&#x8655;&#x7406;&#x9019;&#x4E9B;&#x884C;&#x5167;&#x7684;&#x6578;&#x64DA;&#x3002;&#x4E0B;&#x9EAB;&#x7684;dup3&#x9019;&#x500B;&#x4F8B;&#x5B50;&#x5C31;&#x662F;&#x4EE5;&#x9019;&#x7A2E;&#x5F62;&#x5F0F;&#x4F86;&#x9032;&#x884C;&#x64CD;&#x4F5C;&#x7684;&#x3002;&#x9019;&#x500B;&#x4F8B;&#x5B50;&#x5F15;&#x5165;&#x4E86;&#x4E00;&#x500B;&#x65B0;&#x51FD;&#x6578;ReadFile(&#x5F9E;io/ioutil&#x9019;&#x500B;&#x5305;)&#xFF0C;&#x9019;&#x500B;&#x51FD;&#x6578;&#x6703;&#x628A;&#x4E00;&#x500B;&#x6307;&#x5B9A;&#x540D;&#x5B57;&#x7684;&#x6587;&#x4EF6;&#x5167;&#x5BB9;&#x4E00;&#x6B21;&#x6027;&#x8ABF;&#x5165;&#xFF0C;&#x4E4B;&#x5F8C;&#x6211;&#x5011;&#x7528;strings.Split&#x51FD;&#x6578;&#x628A;&#x6587;&#x4EF6;&#x5206;&#x5272;&#x70BA;&#x591A;&#x500B;&#x5B50;&#x5B57;&#x7B26;&#x4E32;&#xFF0C;&#x4F75;&#x5B58;&#x5132;&#x5230;slice&#x7D50;&#x69CB;&#x4E2D;&#x3002;(Split&#x51FD;&#x6578;&#x662F;strings.Join&#x7684;&#x9006;&#x51FD;&#x6578;&#xFF0C;Join&#x51FD;&#x6578;&#x4E4B;&#x524D;&#x63D0;&#x5230;&#x904E;)</p>
<p>&#x6211;&#x5011;&#x7C21;&#x5316;&#x4E86;dup3&#x9019;&#x500B;&#x7A0B;&#x5E8F;&#x3002;&#x9996;&#x5148;&#xFF0C;&#x4ED6;&#x96BB;&#x8B80;&#x53D6;&#x547D;&#x540D;&#x7684;&#x6587;&#x4EF6;&#xFF0C;&#x800C;&#x4E0D;&#x53BB;&#x8B80;&#x6A19;&#x6E96;&#x8F38;&#x5165;&#xFF0C;&#x56E0;&#x70BA;ReadFile&#x51FD;&#x6578;&#x9700;&#x8981;&#x4E00;&#x500B;&#x6587;&#x4EF6;&#x540D;&#x53C3;&#x6578;&#x3002;&#x5176;&#x6B21;&#xFF0C;&#x6211;&#x5011;&#x5C07;&#x884C;&#x8A08;&#x6578;&#x908F;&#x8F2F;&#x79FB;&#x8FF4;&#x5230;&#x4E86;main&#x51FD;&#x6578;&#xFF0C;&#x56E0;&#x70BA;&#x73FE;&#x5728;&#x9019;&#x500B;&#x908F;&#x8F2F;&#x96BB;&#x6709;&#x4E00;&#x500B;&#x5730;&#x65B9;&#x9700;&#x8981;&#x7528;&#x5230;&#x3002;</p>
<pre><code class="lang-go">gopl.io/ch1/dup3
<span class="hljs-keyword">package</span> main
<span class="hljs-keyword">import</span> (
<span class="hljs-string">&quot;fmt&quot;</span>
<span class="hljs-string">&quot;io/ioutil&quot;</span>
<span class="hljs-string">&quot;os&quot;</span>
<span class="hljs-string">&quot;strings&quot;</span>
)
<span class="hljs-keyword">func</span> main() {
counts := <span class="hljs-built_in">make</span>(<span class="hljs-keyword">map</span>[<span class="hljs-typename">string</span>]<span class="hljs-typename">int</span>)
<span class="hljs-keyword">for</span> _, filename := <span class="hljs-keyword">range</span> os.Args[<span class="hljs-number">1</span>:] {
data, err := ioutil.ReadFile(filename)
<span class="hljs-keyword">if</span> err != <span class="hljs-constant">nil</span> {
fmt.Fprintf(os.Stderr, <span class="hljs-string">&quot;dup3: %v\n&quot;</span>, err)
<span class="hljs-keyword">continue</span>
}
<span class="hljs-keyword">for</span> _, line := <span class="hljs-keyword">range</span> strings.Split(<span class="hljs-typename">string</span>(data), <span class="hljs-string">&quot;\n&quot;</span>) {
counts[line]++
}
}
<span class="hljs-keyword">for</span> line, n := <span class="hljs-keyword">range</span> counts {
<span class="hljs-keyword">if</span> n &gt; <span class="hljs-number">1</span> {
fmt.Printf(<span class="hljs-string">&quot;%d\t%s\n&quot;</span>, n, line)
}
}
}
</code></pre>
<p>ReadFile&#x51FD;&#x6578;&#x8FD4;&#x8FF4;&#x4E00;&#x500B;byte&#x7684;slice&#xFF0C;&#x9019;&#x500B;slice&#x5FC5;&#x9B1A;&#x88AB;&#x8F49;&#x63DB;&#x70BA;string&#xFF0C;&#x4E4B;&#x5F8C;&#x7E94;&#x80FD;&#x5920;&#x7528;string.Split&#x65B9;&#x6CD5;&#x4F86;&#x9032;&#x884C;&#x8655;&#x7406;&#x3002;&#x6211;&#x5011;&#x5728;3.5.4&#x7BC0;&#x4E2D;&#x6703;&#x66F4;&#x8A73;&#x7D30;&#x5730;&#x8B1B;&#x89E3;string&#x548C;byte slice(&#x5B57;&#x7BC0;&#x6578;&#x7D44;)&#x3002;</p>
<p>&#x5728;&#x66F4;&#x5E95;&#x5C64;&#x4E00;&#x4E9B;&#x7684;&#x5730;&#x65B9;&#xFF0C;bufio.Scanner&#xFF0C;ioutil.ReadFile&#x548C;ioutil.WriteFile&#x4F7F;&#x7528;&#x7684;&#x662F;*os.File&#x7684;Read&#x548C;Write&#x65B9;&#x6CD5;&#xFF0C;&#x4E0D;&#x904E;&#x4E00;&#x822C;&#x7A0B;&#x5E8F;&#x54E1;&#x4F75;&#x4E0D;&#x9700;&#x8981;&#x53BB;&#x76F4;&#x63A5;&#x4E86;&#x89E3;&#x5230;&#x5176;&#x5E95;&#x5C64;&#x5BE6;&#x73FE;&#x7D30;&#x7BC0;&#xFF0C;&#x5728;bufio&#x548C;io/ioutil&#x5305;&#x4E2D;&#x63D0;&#x4F9B;&#x7684;&#x65B9;&#x6CD5;&#x5DF2;&#x7D93;&#x8DB3;&#x5920;&#x597D;&#x7528;&#x3002;</p>
<pre><code>Exercise 1.4: &#x8129;&#x6539;dup2&#xFF0C;&#x4F7F;&#x5176;&#x53EF;&#x4EE5;&#x6253;&#x5370;&#x91CD;&#x5FA9;&#x7684;&#x884C;&#x5206;&#x5F46;&#x9F63;&#x73FE;&#x5728;&#x54EA;&#x4E9B;&#x6587;&#x4EF6;&#x3002;
</code></pre>
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