How to make downcase only for first letters in ruby?

Question

ruby

How to write a function in ruby ​​that will make only the first letters in a sentence small.
Example:
Hello Everybody I Am Adam McCartney
Result
hello everybody i am adam mcCartney

Answer 1

"Hello Everybody I Am Adam McCartney".gsub(/(^| )(\w)/) { $1 + $2.downcase }

Answer 2

str.gsub(/\b\w/){|m| m.downcase}