How can two strings be concatenated?

Question

How can I concatenate (merge, combine) two values? For example I have:

tmp = cbind(\"GAD\", \"AB\")
tmp
#      [,1]  [,2]
# [1,] \"GAD\" \"AB\"

Answer 1

Consider the case where the strings are columns and the result should be a new column:

df <- data.frame(a = letters[1:5], b = LETTERS[1:5], c = 1:5)

df$new_col <- do.call(paste, c(df[c("a", "b")], sep = ", ")) 
df
#  a b c new_col
#1 a A 1    a, A
#2 b B 2    b, B
#3 c C 3    c, C
#4 d D 4    d, D
#5 e E 5    e, E

Optionally, skip the [c("a", "b")] subsetting if all columns needs to be pasted.

# you can also try str_c from stringr package as mentioned by other users too!
do.call(str_c, c(df[c("a", "b")], sep = ", "))