Remove the first bracket and its content in a string with R

Question

For instance:

a = '[122][md]+'
b = '[3][md+5]x'

I want to remove the first bracket and the contents in this bracket, and get:

a = '[md]+'
b= '[md+5]x'

Answer 1

You can use regex

> gsub('\\[[0-9]+\\]', '', a)
[1] "[md]+"

Answer 2

Use sub with the pattern \[.*?\] and replace that with empty string.

a <- '[122][md]+'
b <- '[3][md+5]x'
sub("\\[.*?\\]", "", a)
sub("\\[.*?\\]", "", b

Demo