将数据帧的列拆分为多列 [英] Split a column of a data frame to multiple columns

问题描述

我想获取

  before = data.frame（attr = c（1,30 ，4,6），type = c（'foo_and_bar'，'foo_and_bar_2'））
 attr type 
 1 1 foo_and_bar 
 2 30 foo_and_bar_2 
 3 4 foo_and_bar 
 4 6 foo_and_bar_2 
  

并使用 split（）从上面的列类型获得这样的东西：

  attr type_1 type_2 
 1 1 foo bar 
 2 30 foo bar_2 
 3 4 foo bar 
 4 6 foo bar_2 
  

我想出了一些令人难以置信的复杂性，涉及某种形式的应用，但是我已经错位了。看起来太复杂了，不是最好的办法。我可以使用 strsplit 如下，但是不清楚如何将它们重新放回数据框中的2列。

 > strsplit（as.character（before $ type），'_ and_'）
 [[1]] 
 [1]foobar
 
 [[2]] 
 [1]foobar_2
 
 [[3]] 
 [1]foobar
 
 [[4 ]] 
 [1]foobar_2
  

感谢任何指针。我还没有很清楚R列表。

解决方案

使用 stringr :: str_split_fixed

I'd like to take data of the form

before = data.frame(attr = c(1,30,4,6), type=c('foo_and_bar','foo_and_bar_2'))
  attr          type
1    1   foo_and_bar
2   30 foo_and_bar_2
3    4   foo_and_bar
4    6 foo_and_bar_2

and use split() on the column "type" from above to get something like this:

  attr type_1 type_2
1    1    foo    bar
2   30    foo  bar_2
3    4    foo    bar
4    6    foo  bar_2

I came up with something unbelievably complex involving some form of apply that worked, but I've since misplaced that. It seemed far too complicated to be the best way. I can use strsplit as below, but then unclear how to get that back into 2 columns in the data frame.

> strsplit(as.character(before$type),'_and_')
[[1]]
[1] "foo" "bar"

[[2]]
[1] "foo"   "bar_2"

[[3]]
[1] "foo" "bar"

[[4]]
[1] "foo"   "bar_2"

Thanks for any pointers. I've not quite groked R lists just yet.

解决方案

Use stringr::str_split_fixed

library(stringr)
str_split_fixed(before$type, "_and_", 2)

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