"如何创建一个新的字符列，从 r 的数据框中的另一列中删除文本"

Question

我在 R 中有以下数据框

East    24  Consumer    7/18/2018 0:00  Second Class    Pennsylvania    Chairs  USD71.37
East    29  Consumer    9/21/2016 0:00  Standard Class  Pennsylvania    Binders USD9.61
East    33  Consumer    9/21/2016 0:00  Standard Class  Pennsylvania    Binders USD6.85
East    199 Corporate   7/13/2018 0:00  Standard Class  Pennsylvania    Binders USD2.94
East    216 Corporate   1/9/2016 0:00   Standard Class  Ohio    Machines    USD1188
East    222 Consumer    12/27/2016 0:00 First Class Ohio    Binders USD24
East    224 Consumer    12/27/2016 0:00 First Class Ohio    Machines    USD252
East    331 Consumer    9/1/2017 0:00   First Class Pennsylvania    Binders USD28
East    333 Consumer    4/29/2017 0:00  Second Class    Pennsylvania    Binders USD40
East    334 Consumer    4/29/2017 0:00  Second Class    Pennsylvania    Binders USD8

Answer 1

我们可以使用readr<\/code>包中的parse_number<\/code>函数：

这里V10<\/code>是您的最后一个列名：

library(dplyr)
library(readr)

df %>% 
  mutate(newCol = parse_number(V10))

Answer 2

如果该列称为“a”，您可以对字符串进行子设置，然后转换为数字，如下所示：

> a <- c("USD71.37","USD9.61")
> 
> as.numeric(str_sub(a,4,-1))
[1] 71.37  9.61