How can I convert all numbers in a string to hexadecimal using gsub?

Question

I'm trying to convert all numbers in a string to hex. I tried this code:

str.gsub(/(\d+)/, '\1'.to_i.to_s(16))

But this replaces every number with 0 because it modifies the string '\\1' instead of the number that replaces \\1 .

How can I do this correctly using gsub ?

Answer 1

String#gsub accepts a block. The return value of the block is used as the replacement value:

>> str = '100 200'
=> "100 200"
>> str.gsub(/\d+/) { |x| x.to_i.to_s(16) }
=> "64 c8"