在R中：从字段中删除逗号，并使修改后的字段仍然是数据框的一部分 [英] In R: remove commas from a field AND have the modified field remain part of the dataframe

问题描述

我需要从R数据框中的字段中删除逗号。从技术上讲，我已经做到了这一点，但是结果似乎既不是向量也不是矩阵，而且我无法以可用格式将其返回到数据帧中。因此，有一种方法可以删除字段中的逗号，并使该字段保留在数据帧中。

I need to remove commas from a field in an R dataframe. Technically I have managed to do this, but the result seems to be neither a vector nor a matrix, and I cannot get it back into the dataframe in a usable format. So is there a way to remove the commas from a field, AND have that field remain part of the dataframe.

这里是需要删除逗号的字段示例，其结果由我的代码生成：

Here is a sample of the field that needs commas removed, and the results generated by my code:

> print(x['TOT_EMP'])
         TOT_EMP
1    132,588,810
2      6,542,950
3      2,278,260
4        248,760

> y
[1] "c(\"132588810\" \"6542950\" \"2278260\" \"248760\...)"

所需结果是一个数字字段：

The desired result is a numeric field:

       TOT_EMP
1    132588810
2      6542950
3      2278260
4       248760

x<-read.csv("/home/mark/Desktop/national_M2013_dl.csv",header=TRUE,colClasses="character")
y=(gsub(",","",x['TOT_EMP']))
print(y)

推荐答案

gsub（）将返回字符向量，而不是数字向量（这听起来像您想要的）。 as.numeric（）会将字符向量转换回数字向量：

gsub() will return a character vector, not a numeric vector (which is it sounds like you want). as.numeric() will convert the character vector back into a numeric vector:

> df <- data.frame(numbers = c("123,456,789", "1,234,567", "1,234", "1"))
> df
      numbers
1 123,456,789
2   1,234,567
3       1,234
4           1
> df$numbers <- as.numeric(gsub(",","",df$numbers))
> df
    numbers
1 123456789
2   1234567
3      1234
4         1

结果仍然是 data.frame ：

> class(df)
[1] "data.frame"

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