使用NA拆分数据框中的列

Question

我df喜欢这样的:

df <- data.frame(FOO = c('A|B|C', 'A|B', 'B|C', 'A', 'C'))

> df
    FOO
1 A|B|C
2   A|B
3   B|C
4     A
5     C

我希望有这样的输出:

> df
  X1 X2 X3
1 A  B  C
2 A  B
3    B  C
4 A
5       C

到目前为止,我尝试了这个例子:在数据框中的分隔符处拆分列但是没有重复值而没有拆分列,我得到的是:

df <- data.frame(do.call('rbind', strsplit(as.character(df$FOO),'|',fixed=TRUE)))

> df
  X1 X2 X3
1  A  B  C
2  A  B  A
3  B  C  B
4  A  A  A
5  C  C  C

我也得到这个警告:

警告信息:在rbind中(c("A","B","C"),c("A","B"),c("B","C"),"A","C" ):结果列数不是矢量长度的倍数(arg 2)

在这些情况下我该怎么办？最好用baseR

Answer 1

简单地说:

splt <- strsplit(as.character(df$FOO),"\\|")
all_val <- sort(unique(unlist(splt)))
t(sapply(splt,function(x){all_val[!(all_val %in% x)]<-NA;all_val}))


#     [,1] [,2] [,3]
#[1,] "A"  "B"  "C" 
#[2,] "A"  "B"  NA  
#[3,] NA   "B"  "C" 
#[4,] "A"  NA   NA  
#[5,] NA   NA   "C" 

数据:

df <- data.frame(FOO = c('A|B|C', 'A|B', 'B|C', 'A', 'C'))

请注意:

我的版本是base::(不需要库)和一般:

它也适用于:

df <- data.frame(FOO = c('A|B|C', 'A|B', 'B|C', 'A', 'C', 'B|D|F'))

Answer 2

忽略了OP要求base R解决方案.请尝试@ AndreElrico,@ r.user.05apr或@milan的解决方案.

这可以cSplit_e从splitstackshape包中完成:

library(splitstackshape)
cSplit_e(
  data = df,
  split.col = "FOO",
  sep = "|",
  mode = "value",
  type = "character",
  fill = " ",
  drop = TRUE
)
#  FOO_A FOO_B FOO_C
#1     A     B     C
#2     A     B      
#3           B     C
#4     A            
#5                 C

在以下df的情况下也可以使用(参见上面的OP评论).

(df1 <- data.frame(FOO = c('A|B|C', 'A|B', 'B|C', 'A', 'C', 'B|D|F')))
#    FOO
#1 A|B|C
#2   A|B
#3   B|C
#4     A
#5     C
#6 B|D|F

cSplit_e(df1, "FOO", "|", "value",  "character", TRUE, fill = " ")
#  FOO_A FOO_B FOO_C FOO_D FOO_F
#1     A     B     C            
#2     A     B                  
#3           B     C            
#4     A                        
#5                 C            
#6           B           D     F