RegEx帮助（13位长度数字，以特定数字结尾）

Question

Another RegEx question for a search I'm trying to do.

The Problem : Determine if user input is 13 digits long (numbers only) and ends with 52,56, or 57.

My current not working solution : [0-9]52|56|57${13} . I also tried [0-9]52|56|57{13}$ but no dice.

Help is appreciated.

Answer 1

Try this regular expression:

^[0-9]{11}(52|56|57)$

This is what it means:

^          Start of string
[0-9]      Any character in 0-9
{11}       The previous token must match exactly 11 times.
(52|56|57) Alternation - any one of the possibilities must match
$          End of string

You could also in this case simplify it to:

^[0-9]{11}5[267]$

Answer 2

You have 13 digits 11 of which can be any digit and the next two must be 52,56, or 57. 11 digits in regex notation is something like \\d{11} . The 'or' operator is denoted by the symbole | so 52 or 56 or 57 becomes 52|56|57 . The resulting regex looks like \\d{11}(52|56|57) . Parentheses are used to disambiguate.

Remember that you can construct complex regular expressions from simpler ones. This approach works always ;)