str.capitalize
Return a copy of str capitalized # "string" => "String"
str.downcase
Return a lowercase copy of str # "STRING" => "string"
str.swapcase
Return a swapped case copy of str # "String" => "sTRING"
str.upcase
Return a uppercase copy of str # "string" => "STRING"
Search / Replace I
str.end_with?(str2)
Returns true if str ends with str2
str.include?(str2)
Return true if str includes str2
str.index(str2)
Return index of first occurrence of str2 in str
str.rindex(str2)
Return the index of the last occurrence of str2 in str
str.start_with?(str2)
Return true if str starts with str2