25 Apr '16, 7am
Speed up String#blank? Regex by schneems · Pull Request #24658 · rails/rails · GitHub: Follow up on 697384d… https://t.co/a3yyUH8q3u
[email protected] #commitcomment-17184696 . The regex to detect a blank string `/\A[[:space:]]*\z/` will loop through every character in the string to ensure that all of them are a `:space:` type. We can invert this logic and instead look for any non-`:space:` characters. When that happens, we would return on the first character found and the regex engine does not need to keep looking. Thanks @nellshamrell for the regex talk at LSRC. By defining a "blank" string as any string that does not have a non-whitespace character (yes, double negative) we can get a substantial speed bump. Also an inline regex is (barely) faster than a regex in a constant, since it skips the constant lookup. A regex literal is frozen by default. ```ruby require 'benchmark/ips' def string_generate str = " abcdefghijklmnopqrstuvwxyz\t".freeze str[rand(0..(str.length - 1))] * rand(0..23) end strings = 100....