XML Regex - Negative match

Question

I have a problem with negative lookahead in XSD pattern. When I specified:

<xs:pattern value="^(?!(00|\+\d))\d{6,}$"/>

then I got an error message:

Value '^(?!(00|\+\d))\d{6,}$' is not a valid XML regular expression.

Any idea why it does not work?

In online javascript validator it works fine (e.g. here under unit tests section click on "run test").

I need to validate phone numbers. The phone number cannot include international prefixes (+\d) and (00).

Thanks

XSD [does not support](http://www.regular-expressions.info/xml.html) lookaround. — logi-kal, Jul 18 '16 at 12:00
@horcrux, where can I find what is not supported in XSD pattern? — peterko, Jul 18 '16 at 12:52
@peterko Aren't you satisfied with the answer below? If you need more details, ask the person who gave you an answer. — Wiktor Stribiżew, Jul 18 '16 at 13:21
Note that in XSD, `\d` matches all Unicode digits, not just `[0-9]` — Wiktor Stribiżew, Jul 18 '16 at 13:23
[Here](http://stackoverflow.com/questions/36860613/how-to-properly-escape-regular-expression-pattern-in-xsd-schema/36862803#36862803) is an SO question where some constructs not supported in XSD regex are described. — Wiktor Stribiżew, Jul 18 '16 at 13:25
@WiktorStribiżew thanks a lot, your overview saved my time :) — peterko, Jul 18 '16 at 15:10
I provided an answer below summarizing the main points and in a more concise way. — Wiktor Stribiżew, Jul 18 '16 at 15:12

score 2 · Accepted Answer · answered Jul 18 '16 at 12:07

Try the following regex:

[1-9][0-9]{5,} | 0[1-9][0-9]{4,}

This matches a number which does not begin with zero and is followed by any digit (including zero) 5 or more times, and it also matches a number which starts with zero and is not immediately followed by zero, but after that can have 0-9.

score 0 · Answer 2 · answered Jul 18 '16 at 13:45

I will add my deleted comment as an answer:

([1-9][0-9]|[0-9][1-9])[0-9]{4,}

See the regex demo.

The regex should work well for your scenario because

([1-9][0-9]|[0-9][1-9]) - matches either 1 digit from 1-9 ranges and any digit after or (|) any 1 digit followed with any digit but 0 - making up 2 digits
[0-9]{4,} - matches 4 and more any digits.

This pattern only matches a full/entire string because all regex patterns inside XSD pattern are anchored by default (so, you do not have to and can't enclose the pattern with ^ and $).

Right, there is no lookaround support in XSD regex (no lookaheads, nor lookbehinds). Besides, XSD regex has other interesting limitations/features:

^ and $ anchors
Non-capturing groups like (?:...) (use capturing ones instead)
/ should not be escaped, do not use \/
\d should be written as [0-9] to only match ASCII digits (same as in .NET)
Back-references like \1, \2 are not supported.
No word boundaries are supported either.

See some more XSD regex description at regular-expressions.info.

XML Regex - Negative match

2 Answers2

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