Why is this regex allowing a caret?
RegexRegex Problem Overview
^(?=.*[0-9])(?=.*[A-z])[0-9A-z-]{17}$
Should match "17 alphanumeric chars, hyphens allowed too, must include at least one letter and at least one number"
It'll correctly match:
ABCDF31U100027743
and correctly decline to match:
AB$DF31U100027743
(and almost any other non-alphanumeric char)
but will apparently allow:
AB^DF31U100027743
Regex Solutions
Solution 1 - Regex
Because your character class [A-z]
matches this symbol.
[A-z]
matches [
, \
, ]
, ^
, _
, `
, and the English letters.
Actually, it is a common mistake. You should use [a-zA-Z]
instead to only allow English letters.
Here is a visualization from Expresso, showing what the range [A-z]
actually covers:
So, this regex (with i
option) won't capture your string.
^(?=.*[0-9])(?=.*[a-z])[0-9a-z-]{17}$
In my opinion, it is always safer to use Ignorecase
option to avoid such an issue and shorten the regex.
Solution 2 - Regex
>regex uses ASCII printable characters from the space to the tilde range.
Whenever we use [A-z]
token it matches the following table highlighted characters. If we use [ -~]
token it matches starting from SPACE
to tilde.
Solution 3 - Regex
You're allowing A-z (capital 'A' through lower 'z'). You don't say what regex package you're using, but it's not necessarily clear that A-Z and a-z are contiguous; there could be other characters in between. Try this instead:
^(?=.*[0-9])(?=.*[A-Za-z])[0-9A-Za-z-]{17}$
It seems to meet your criteria for me in regexpal.