September 2013
Intermediate to advanced
264 pages
5h
Chinese
Content preview from Bad Data 技術手冊
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第三章：資料是要給人類使用，而非給機器使用
> as.numeric(year13boys)
[1] 34 37 33
> as.numeric(year13boys) < 3
[1] FALSE FALSE FALSE
> all(as.numeric(year13boys) < 3)
[1] FALSE
上方的程式碼告訴電腦要去執行本來我們要自己用眼睛做的任務。
讀取跨數個檔案的資料
我們要解決的第二個問題，就是有超過 490 張電子試算表要被確認。
若所有學校的電子試算表都是使用完全一樣的格式，那麼這個程序就很簡單，只要對每
個學校重複執行這些動作即可。不幸的是，事情並沒有那麼簡單，因為有些學校使用不
同的電子試算表格式。舉例來說，Alpha School 只有男學生的結果（沒有任何的列是在
統計女學生的數量），所以讓我們感興趣的資料便是在電子試算表中的第 8、10 以及 12
列（見圖 3-7）。
圖 3-7 2010 年 Alpha School 完成 NCEA 的學生數量
另一個範例是 Delta Education Centre，只有
一列
男學生的資料，而該列又沒有值（見圖
3-8）。
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答案：撰寫程式
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圖 3-8 2010 年 Delta Education Centre
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