Johnny Strings Johnny Strings - 1 year ago 83
R Question

R Why is paste replacing characters with digits?

In this given R code...

df1 <- c("a","b","a","b","b","c","b","c","c","d","c","d")
dim(df1) = c(4,3)
df1 <-

for (i in 1:nrow(df1)) {
df1[i,"paste"] <- paste(df1[i,!names(df1) %in% c("paste")],collapse="")

... I am expecting to see:

V1 V2 V3 V4 paste
a b a b abab
b c b c bcbc
c d c d cdcd

... but am instead seeing:

V1 V2 V3 V4 paste
a b a b 1111
b c b c 2222
c d c d 3333

This seems trivial, and I do not understand what's wrong with code. Could anyone explain how my code is producing the given output? Also, any other ideas on how to produce the simple output I desire? Thanks.

Answer Source

The reason is that df1[i,!names(df1) %in% c("paste")] returns a data frame. You can unlist the data frame in order for paste to work properly:

for (i in 1:nrow(df1)) {
    df1[i,"paste"] <- paste(unlist(df1[i,!names(df1) %in% c("paste")]),collapse="")
#                           ^^^^^^

#  V1 V2 V3 V4 paste
#1  a  b  a  b  abab
#2  b  c  b  c  bcbc
#3  c  d  c  d  cdcd

Here is how paste works on data frame if df1 contains factor variable:

paste(df1[1:4], collapse = "")
# [1] "1:31:31:31:3"

As an alternative, this should also work for you:

df1$paste =, df1[1:4])
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