如何在 R 数据框中替换与某些特定值组合的 $ 符号?
r programmingserver side programmingprogramming更新于 2025/6/24 18:52:17
有时我们会得到非常脏的数据，这就是数据分析如此困难的原因。大多数数据科学家都在寻找干净的数据，但这几乎是不可能的，因为数据仓库通常只关注数据的可用性，而不是数据的质量。其中一个令人费解的情况是将不必要的值随机地放置在不同的位置，$ 符号也属于这种类型的值。我们可以使用 lapply 函数从 R 数据框中删除它。
示例
考虑以下数据框:
> x<-sample(c("A","$B","C"),20,replace=TRUE)
> y<-sample(c("I","II","$II"),20,replace=TRUE)
> df1<-data.frame(x,y)
> df1
输出
x y 1 C $II 2 C II 3 A I 4 $B $II 5 $B $II 6 A I 7 A $II 8 C I 9 $B II 10 $B II 11 C $II 12 A II 13 $B II 14 C I 15 C $II 16 C I 17 C II 18 $B I 19 $B II 20 C $II
从 df1 中的每个位置删除 $ 符号:
示例
> df1<-lapply(df1,gsub,pattern='\$',replacement='') > df1 $x
输出
[1] "C" "C" "A" "B" "B" "A" "A" "C" "B" "B" "C" "A" "B" "C" "C" "C" "C" "B" "B" [20] "C"
示例
$y
输出
[1] "II" "II" "I" "II" "II" "I" "II" "I" "II" "II" "II" "II" "II" "I" "II" [16] "I" "II" "I" "II" "II"
我们来看另一个例子:
示例
> Price<-sample(c("1$","2$","3$","4$"),20,replace=TRUE)
> Group<-sample(c("$First","$Second","Third"),20,replace=TRUE)
> df2<-data.frame(Price,Group)
> df2
输出
Price Group 1 3$ $Second 2 2$ Third 3 1$ Third 4 2$ $Second 5 2$ $First 6 4$ $First 7 2$ $First 8 3$ $First 9 2$ Third 10 4$ Third 11 3$ $First 12 3$ Third 13 3$ $Second 14 2$ $First 15 4$ Third 16 3$ $First 17 4$ Third 18 2$ $First 19 2$ $Second 20 3$ Third
从 df2 中的每个位置删除 $ 符号:
示例
> df2<-lapply(df2,gsub,pattern='\$',replacement='') > df2
输出
$Price [1] "3" "2" "1" "2" "2" "4" "2" "3" "2" "4" "3" "3" "3" "2" "4" "3" "4" "2" "2" [20] "3" $Group [1] "Second" "Third" "Third" "Second" "First" "First" "First" "First" [9] "Third" "Third" "First" "Third" "Second" "First" "Third" "First" [17] "Third" "First" "Second" "Third"
