字符类中的字符顺序在正则表达式中重要吗

Question

I was using character class in regular expression to split a string. I had an assumption that order of characters in the character class does not matter.

Following are the two patterns I was using to split the string "123.3+23+23.3" .

[+/*-]

[+*-/]

For the first pattern I got the output as:

123.3
23
23.3

For the second pattern I got the output as :

123
3
23
23
3

I've no idea, why I am getting the different outputs. Please help me out.

Answer 1

Within a character class, - is a range operator (as in [af] is the same as [abcdef] ). So if you want to include an actual - in your range, it must be the first or last character.

Therefore, your first example will match + / * - , while your second will match + / * - , . .