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Developing a JavaScript regex, we found out some weird behaviour.
For following pattern: [\'-=]
The character * is accepted. (', -, = are also accepted but this is expected.)
We can replace '=' by any character. If we change pattern characters order, it does not work anymore.
Anyone got an idea about this?
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*. * , returns strings beginning with any combination and any amount of characters (the first asterisk), and can end with any combination and any amount of characters (the last asterisk). This selects every single string available.
represents any single character (usually excluding the newline character), while * is a quantifier meaning zero or more of the preceding regex atom (character or group). ? is a quantifier meaning zero or one instances of the preceding atom, or (in regex variants that support it) a modifier that sets the quantifier ...
Basically (0+1)* mathes any sequence of ones and zeroes. So, in your example (0+1)*1(0+1)* should match any sequence that has 1. It would not match 000 , but it would match 010 , 1 , 111 etc. (0+1) means 0 OR 1.
The asterisk ( * ): The asterisk is known as a repeater symbol, meaning the preceding character can be found 0 or more times. For example, the regular expression ca*t will match the strings ct, cat, caat, caaat, etc.
The "-" character in the middle of the pattern is what's causing your problem. The "-" character is special inside character groups like that, and it means "all the characters between". Thus, "'-=" means "all characters from "'" through "=". It happens that "*" is in that range.
To fix it, re-order the list of characters so that the "-" is at the end, or else quote it with a backslash.
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