R：将data.frame（包括数字和字符）添加到另一个data.frame中的单元格

Question

What I want to do is like this:

> a <- data.frame (col1=c(NA,NA,NA,NA), col2=c(NA,NA,NA,NA), col3=c(NA,NA,NA,NA))
> b <- data.frame(cola="test", colb=1)
>  a[1,2:3] <- b  
> a
  col1 col2 col3
1   NA  test    1
2   NA   NA   NA
3   NA   NA   NA
4   NA   NA   NA

However, what I got by executing the code above is :

> a
  col1 col2 col3
1   NA    1    1
2   NA   NA   NA
3   NA   NA   NA
4   NA   NA   NA

How can I add characters to specific rows in another data.frame?

I could add characters to a single cell, but it seems characters are automatically converted to numbers if I add two or more.

> a[1,2] <- "test"
> a
  col1 col2 col3
1   NA test   NA
2   NA <NA>   NA
3   NA <NA>   NA
4   NA <NA>   NA

Answer 1

This happens because b$cola is a factor. It will work, if you transform the column values to character strings.

b$cola <- as.character(b$cola)
a[1,2:3] <- b
a
#   col1 col2 col3
# 1   NA test    1
# 2   NA <NA>   NA
# 3   NA <NA>   NA
# 4   NA <NA>   NA