在列中拆分分隔字符串并作为新行插入 [英] Split delimited strings in a column and insert as new rows

问题描述

我有一个如下的数据框:

I have a data frame as follow:

+-----+-------+
|  V1 |  V2   |
+-----+-------+
|  1  | a,b,c |
|  2  | a,c   |
|  3  | b,d   |
|  4  | e,f   |
|  .  | .     |
+-----+-------+

每个字母表都是一个用逗号分隔的字符.我想在每个逗号上拆分 V2 并将拆分字符串作为新行插入.例如，所需的输出将是:

Each of the alphabet is a character separated by comma. I would like to split V2 on each comma and insert the split strings as new rows. For instance, the desired output will be:

+----+----+
| V1 | V2 |
+----+----+
|  1 |  a |
|  1 |  b |
|  1 |  c |
|  2 |  a |
|  2 |  c |
|  3 |  b |
|  3 |  d |
|  4 |  e |
|  4 |  f |
+----+----+

我正在尝试使用 strsplit() 先吐出 V2，然后将列表转换为数据框.它没有用.任何帮助将不胜感激.

I am trying to use strsplit() to spit V2 first, then cast the list into a data frame. It didn't work. Any help will be appreciated.

推荐答案

这是另一种方法..

df <- read.table(textConnection("1|a,b,c
2|a,c
3|b,d
4|e,f"), header = F, sep = "|", stringsAsFactors = F)

df
##   V1    V2
## 1  1 a,b,c
## 2  2   a,c
## 3  3   b,d
## 4  4   e,f

s <- strsplit(df$V2, split = ",")
data.frame(V1 = rep(df$V1, sapply(s, length)), V2 = unlist(s))
##   V1 V2
## 1  1  a
## 2  1  b
## 3  1  c
## 4  2  a
## 5  2  c
## 6  3  b
## 7  3  d
## 8  4  e
## 9  4  f

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