What is the purpose of “!” and “?” at the end of method names?

Question

Sometimes I see methods in Ruby that have \"?\" and \"!\" at the end of them, e.g:

name = \"sample_string\"
name.reverse
name.reverse!
name.is_binary_data?
<         


        

Answer 1

Question mark indicates that the method returns boolean. Already answered here:

What does the question mark operator mean in Ruby?

The bang indicates that the method acts on the object itself. Already answered here:

Why are exclamation marks used in Ruby methods?