Question

Given a string, let’s see “rxrx” , how can I convert the string into “rXrX”, put it another way:
turn all the lower case ‘x’ in the string into the upper case ‘X’ in ruby? Thanks in advance

Answer 1

One way:

"rxrx".gsub(/(x)/) { |s| s.upcase }

The only reason I suggest this instead of just normal substitution (gsub("x", "X")) is because it’d work well if there were more than one character you wanted to make uppercase:

"rxbrx".gsub(/([xb])/) { |s| s.upcase }