casecmp to Compare Strings

Today I learned about casecmp and casecmp? to compare strings in ruby.

casecmp compares the downcase of both strings and returns 1 if the compared string is smaller, -1 if it's larger, and 0 if they are equal (and nil if they can't be compared).

"hashrocket".casecmp("hashrocket") # => 0
"hashrocket".casecmp("hAsHrOcKeT") # => 0
"hashrocket".casecmp("hashrocket123") # => -1
"hashrocket".casecmp("hashrock") # => 1
"hashrocket".casecmp(123) # => nil

casecmp? does the same comparison but just returns a boolean.

"hashrocket".casecmp("hAsHrOcKeT") # => true
"hashrocket".casecmp("hashrock") # => false
"hashrocket".casecmp(123) # => nil

h/t Brian Dunn