dplyr将字符串拆分为逗号分隔列表 [英] dplyr split string into a comma separated list

问题描述

我正在尝试使用dplyr将一个字符串拆分成逗号分隔的字符串，我没有太多的运气。

I'm trying to use dplyr to split a string into a comma separated string and I'm not having much luck.

dat<-data.frame(key=1:4,labels=c('a','ab','abc','b'))

我试图将标签栏设为c（'a'，'a，b'，'a，b，c'，'b'）

I'm trying to get the labels column to be c('a','a,b','a,b,c','b')

我尝试过以下所有变体，但似乎没有任何效果。

I've tried all of the below variations but nothing seems to work.

dat %>%
  mutate(labels=str_split(labels,''))

dat %>%
  mutate(labels=str_split(labels,'')[[1]])

dat %>%
  mutate(labels=paste(str_split(labels,''),collapse=','))

推荐答案

dplyr 或 mutate 与您的问题无关。您的问题更多的是尝试将列表（由 str_split 返回）作为向量。

dplyr or mutate has nothing to do with your question. Your problems are more along the lines of trying to treat a list (returned by str_split) as a vector.

我会写一个小功能：

comma_sep = function(x) {
    x = strsplit(as.character(x), "")
    unlist(lapply(x, paste, collapse = ','))
}

然后您可以

mutate(dat, labels = comma_sep(labels))
#   key labels
# 1   1      a
# 2   2    a,b
# 3   3  a,b,c
# 4   4      b

但是，当然，你也可以将该功能的肉块塞进一行。

But of course you could jam the meat of the function into that one line as well.

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