Using .downcase or .upcase on strings containing umlauts does not work as expected in Ruby versions before 2.4. It leaves the umlauts unchanged:
"Über".downcase
=> "Über"
"Ärger".downcase
=> "Ärger"
The very same applies for french accents (Thanks Guillaume!):
"Être ou ne pas être, telle est la question".downcase
=> "Être ou ne pas être, telle est la question"
Obviously, this leads to problems when comparing strings:
"Über".downcase == "über"
=> false
In Rails you can use ActiveSupports' multibyte chars Show archive.org snapshot to avoid that problem. It gives you a wrapped, correctly encoded version of your string:
"Ärger".mb_chars.downcase
#<ActiveSupport::Multibyte::Chars:0x7f60b1e58dc8 @wrapped_string="ärger">
Comparison works like expected now:
"Über".mb_chars.downcase == "über"
=> true
Posted by Thomas Eisenbarth to makandra dev (2012-01-09 17:33)