如何用Base R一行代码拆分数据框中含斜杠的行？

Hey there! Let's start by confirming your original data frame:

mydf <- data.frame(a=c('A','B','C','D/E','F','G/H','I/J','K','L'), b=c(1,2,3,'4/5',6,'7/8','9/10',11,12))
mydf
#    a    b
# 1  A    1
# 2  B    2
# 3  C    3
# 4 D/E  4/5
# 5  F    6
# 6 G/H  7/8
# 7 I/J 9/10
# 8  K   11
# 9  L   12

Here's a tight one-liner using only Base R that transforms this into your desired mydf2:

mydf2 <- do.call(rbind, lapply(1:nrow(mydf), function(i) setNames(data.frame(strsplit(as.character(mydf$a[i]), "/")[[1]], strsplit(as.character(mydf$b[i]), "/")[[1]]), names(mydf))))

Let me break down the logic so you know what's going on:

• lapply(1:nrow(mydf), ...) loops through every row of your data frame
• For each row, strsplit(as.character(col), "/")[[1]] splits the value in columns a and b at the slash (we convert to character first since some values might be stored as factors)
• We wrap those split results into a tiny data frame and use setNames to keep the original column names
• do.call(rbind, ...) stacks all those tiny data frames into a single, cleaned-up data frame

If you run that, you'll get exactly the output you wanted:

mydf2
#    a  b
# 1  A  1
# 2  B  2
# 3  C  3
# 4  D  4
# 5  E  5
# 6  F  6
# 7  G  7
# 8  H  8
# 9  I  9
# 10 J 10
# 11 K 11
# 12 L 12

内容的提问来源于stack exchange，提问作者DaniCee