拆分数据框列，其中新列值取决于原始数据

Question

我经常使用数据框，这些数据框的列包含需要分隔的字符串值。这是数据输入程序中的 "select multiple" 选项的结果（不幸的是我无法更改）。我试过 tidyr::separate 但没有正确排序结果。一个例子：

require(tidyr)
df = data.frame(
  x = 1:3,
  sick = c(NA, "malaria", "diarrhoea malaria"))

df <- df %>%
  separate(sick, c("diarrhoea", "cough", "malaria"),
           sep = " ", fill = "right", remove = FALSE)

但我希望结果看起来像这样：

df2 = data.frame(
  x = 1:3,
  sick = c(NA, "malaria", "diarrhoea malaria"),
  diarrhoea = c(NA, NA, "diarrhoea"),
  cough = c(NA, NA, NA),
  malaria = c(NA, "malaria", "malaria"))

任何正确方向的帮助将不胜感激。

Answer 1

我们可以试试 separate_rows 和 dcast

library(tidyr)
library(reshape2)
library(dplyr)
separate_rows(df, sick) %>%
  mutate(sick = factor(sick, levels = c("diarrhoea", "cough", "malaria")), sick1 = sick) %>% 
  dcast(., x~sick, value.var = "sick1", drop=FALSE) %>%
  bind_cols(., df[2]) %>%
  select(x, sick, diarrhoea, cough, malaria) 
#  x              sick diarrhoea cough malaria
#1 1              <NA>      <NA>  <NA>    <NA>
#2 2           malaria      <NA>  <NA> malaria
#3 3 diarrhoea malaria diarrhoea  <NA> malaria

或者另一种选择是使用 splitstackshape 中的 cSplit 和 data.table

中的 dcast

library(splitstackshape)
dcast(cSplit(df, "sick", " ", "long")[, sick:= factor(sick, levels = 
    c("diarrhoea", "cough", "malaria"))], x~sick, value.var = "sick", drop = FALSE)[,
       sick := df$sick][]

拆分数据框列，其中新列值取决于原始数据

Splitting a dataframe column where new column values depend upon original data

r

tidyr