Specs

downcase(t(), :default | :ascii | :greek | :turkic) :: t()

Converts all characters in the given string to lowercase according to mode.

mode may be :default, :ascii, :greek or :turkic. The :default mode considers all non-conditional transformations outlined in the Unicode standard. :ascii lowercases only the letters A to Z. :greek includes the context sensitive mappings found in Greek. :turkic properly handles the letter i with the dotless variant.

Examples

iex> String.downcase("ABCD")
"abcd"

iex> String.downcase("AB 123 XPTO")
"ab 123 xpto"

iex> String.downcase("OLÁ")
"olá"

The :ascii mode ignores Unicode characters and provides a more performant implementation when you know the string contains only ASCII characters:

iex> String.downcase("OLÁ", :ascii)
"olÁ"

The :greek mode properly handles the context sensitive sigma in Greek:

iex> String.downcase("ΣΣ")
"σσ"

iex> String.downcase("ΣΣ", :greek)
"σς"

And :turkic properly handles the letter i with the dotless variant:

iex> String.downcase("Iİ")
"ii̇"

iex> String.downcase("Iİ", :turkic)
"ıi"