# Issue

*This Content is from Stack Overflow. Question asked by Sverdo *

So I have a a dataframe,df: `df = data.frame(c("",1,1),c(1,"",1),c(1,1,""))`

I want to loop through the dataframe and replace the values in the first and second column, if they are empty, with the value in the third column if it has a value in it:

```
n = nrow(df)
for(i in 1:n)df[i,] <-{
if(df[i,1] == "" & df[i,2] == "" & df[i,3] != ""){
df[i,1] = df[i,3]
df[i,2] = df[i,3]
}
}
```

However, I get the following error:

`error in x[[jj]][iseq] <- vjj : replacement has length zero.`

I’ve been trying for quite some time, but can’t figure our what I’m doing wrong. Any help would be much appreciated.

# Solution

Since R is vectorized you do not need a loop:

```
df <- structure(list(A = c("1", "1", "1"), B = c("1", "1", "1"), C = c("1",
"1", "")), row.names = c(NA, -3L), class = "data.frame")
```

Note your data are character vectors as in your example data. The answer will differ slightly if they are numeric.

```
df$A[df$A==""] <- df$C[df$A==""]
df$B[df$B==""] <- df$C[df$B==""]
df
# A B C
# 1 1 1 1
# 2 1 1 1
# 3 1 1
```

This Question was asked in StackOverflow by Sverdo and Answered by dcarlson It is licensed under the terms of CC BY-SA 2.5. - CC BY-SA 3.0. - CC BY-SA 4.0.