According to the docs, String.split/1…

Divides a string into substrings at each Unicode whitespace occurrence…

(emphasis mine)

But I found that it doesn’t do this for U+00A0 “NO-BREAK SPACE” (UTF-8 <<194, 160>>). Maybe others too? No-break space is unicode whitespace and it’s marked as such in the Elixir Unicode property list.

Here’s the unexpected behavior I see (Elixir 1.14):

iex(1)> nbsp = <<194, 160>>
" "
iex(2)> s = Enum.join ["one", "two", "three"], nbsp
"one two three"
iex(3)> String.split s
["one two three"]

I expected it to split on the nbsp, producing the input, ["one", "two", "three"].

I traced the code for String.split/1 to break() here: elixir/lib/elixir/unicode/unicode.ex at main · elixir-lang/elixir · GitHub. It looks ok to me, though.

Background: This caused problems for me parsing some text. I didn’t realize that this is valid Unicode because String.split/1 and Regex.run where failing on it (although for two different reasons).