how to assign value to a dataframe in ifelse query

Question

I'm tring to assign dataframe value to a dataframe in ifelse query,but failed.I have no idea about that

df <- data.frame(x=c('a','g','s'),y=c(2,3,4))
df_1 <- ifelse(2>1,df,NULL)

execute and get the following result:

> df_1
[[1]]
[1] a g s
Error in if (n <= 1L || lenl[n] <= width) n else max(1L, which.max(lenl >  : 
  missing value where TRUE/FALSE needed

the actual results should be

> df
  x y
1 a 2
2 g 3
3 s 4

score 0 · Answer 1 · answered May 14 '19 at 01:26

0

The ifelse function works with scalars and vectors, but maybe not with data frames. Try using a regular if-else statement:

if (2 > 1) {
    df_1 <- df
}
else {
    df_1 <- NULL
}

answered May 14 '19 at 01:26

Tim Biegeleisen

2

You can do this with `ifelse`, too: `ifelse(2 > 1, df_1 <- df, df_1 <- NA)` – andrew_reece May 14 '19 at 01:33
@andrew_reece Brilliant +1. I had no idea that the predicate can also be an assignment. – Tim Biegeleisen May 14 '19 at 01:41
1

Thanks @Tim Biegeleisen, I can't claim credit though - found it here: https://stackoverflow.com/a/49695736/2799941 – andrew_reece May 14 '19 at 01:42

1 Answers1