What does this pattern ^ [% w -.] + $ Mean in Lua?

Question

Just stumbled upon this pattern, which I really don't understand:

^[%w-.]+$

And could you give some examples to match this expression?

Answer 1

Valid in Lua, where the %w(almost) equivalent \win other languages

^[%w-.]+$ means matching a string that consists of alphanumeric characters (letters and numbers), dashes, or periods.

Explanation

• The core ^claims that we are at the beginning of the line
• A character class [%w-.]corresponds to one character, which is a letter or number (value %w), dash, or period. That would be equivalent [\w-.]in JavaScript
• +
• $ ,

Lua

Answer 2

. : w- , . %w\-.

^ [% \-.] + $

:

• ^
• [%w\-.]+ ,
  • + : , , []
  • %w % w ( )
  • \- -
  • . .
• $

Edit

, . POSIX.

@zx81:

• %w \w Lua, - "_"