removing digit (zero) of a column and create a new column in data frame

Question

For example if I have

  ID rout
1  1 0123
2  2 0245
3  3 0789
4  4 0963
5  5 6779
6  6  056
7  7  zxc
8  8  asd
9  9  1234

I wonder how I can remove only the first digit of the rout column for observations with 4 characters and only when it (the first character) is zero, and create a column (rout2) like below:

   ID rout rout2
1  1 0123   123
2  2 0245   245
3  3 0789   789
4  4 0963   963
5  5 6779  6779
6  6  056   056
7  7  zxc   zxc
8  8  asd   asd
9  9  1234  1234

Answer 1

Edit after discussion in the comments

In order to remove only the first digit when it is zero, and only for 4-digit alphanumeric values, you can do

data$rout2 <- ifelse(nchar(data$rout) == 4, sub("^[0]", "", data$rout), data$rout)

Output

#   ID rout rout2
# 1  1 0123   123
# 2  2 0245   245
# 3  3 0789   789
# 4  4 0963   963
# 5  5 6779  6779
# 6  6  056   056
# 7  7  zxc   zxc
# 8  8  asd   asd
# 9  9 1234  1234