r - 两列之间的数据框操作并将结果添加为第三列

Question

给定一个包含列的数据框:

• “length1”整数字符
• "length2"每个元素都是一串数字

我想获得 length2 列相对于 length1 列的百分比。所以类似于 df$length2/df$lenght1 *100。请查看以下最小示例:

> df=data.frame(length1=c("10","12","14"))
> df$length2=list("2,3,4","4,5,3","3,2,6")
> df

length1 length2
1      10   2,3,4
2      12   4,5,3
3      14   3,2,6

> dfresult=df
> dfresult$resultInPercent=list("20,30,40","33,41,25","21,14,42")
> dfresult

  length1 length2 resultInPercent
1      10   2,3,4        20,30,40
2      12   4,5,3        33,41,25
3      14   3,2,6        21,14,42

我无法让它工作，我的方法是:

dfresult=apply(df, 1, function(x) 
{

  lapply(lapply(lapply(x$length2,strsplit,split=","),as.numeric),function(y)
     {
        round(as.numeric(y)/as.numeric(x$length1)*100)
     }

  )
 } 
)

Error in lapply(lapply(x$length2, strsplit, split = ","), as.numeric) : (list) object cannot be coerced to type 'double'

我在这里放弃了，感觉我所做的事情太复杂了。

Answer 1

另一个想法:

library(dplyr)
library(tidyr)

df %>%
  separate_rows(length2) %>% 
  mutate_all(funs(as.numeric(as.character(.)))) %>%
  group_by(length1) %>%
  summarise(l2 = list(length2), 
            l3 = list(round(100 * length2 / length1))) 

给出:

## A tibble: 3 x 3
#  length1        l2        l3
#    <dbl>    <list>    <list>
#1      10 <dbl [3]> <dbl [3]>
#2      12 <dbl [3]> <dbl [3]>
#3      14 <dbl [3]> <dbl [3]>

---

这会将结果存储在 list 中，以便于进一步操作:

#Observations: 3
#Variables: 3
#$ length1 <dbl> 10, 12, 14
#$ l2      <list> [<2, 3, 4>, <4, 5, 3>, <3, 2, 6>]
#$ l3      <list> [<20, 30, 40>, <33, 42, 25>, <21, 14, 43>]