CODEWITHSUNDEEP
regexphone-number
sivabudh
sivabudh

Reputation: 32635

Regular expression to match phone number?

I want to match a phone number that can have letters and an optional hyphen:

In other words, there can be at most one hyphen but if there is no hyphen, there can be at most seven 0-9 or A-Z characters.

I dont know how to do and "if statement" in a regex. Is that even possible?

Upvotes: 3

Views: 5818

Answers (6)

ListenSoftware Louise Ai Agent
ListenSoftware Louise Ai Agent

Reputation: 4233

I use a or with two patterns 7 alpha numeric characters or 3 alpha numeric character a hyphen and 4 alpha numeric characters

def check_string(string):
    if re.match(r'^[A-Z0-9]{7}$|^[A-Z0-9]{3}-[A-Z0-9]{4}$', string):
        return True
    else:
        return False

Upvotes: 0

Heath Hunnicutt
Heath Hunnicutt

Reputation: 19457

You seek the alternation operator, indicated with pipe character: |

However, you may need either 7 alternatives (1 for each hyphen location + 1 for no hyphen), or you may require the hyphen between 3rd and 4th character and use 2 alternatives.

One use of alternation operator defines two alternatives, as in:

({3,3}[0-9A-Za-z]-{4,4}[0-9A-Za-z]|{7,7}[0-9A-Za-z])

Upvotes: 4

Artelius
Artelius

Reputation: 49089

Supposing that you want to allow the hyphen to be anywhere, lookarounds will be of use to you. Something like this:

^([A-Z0-9]{7}|(?=^[^-]+-[^-]+$)[A-Z0-9-]{8})$

There are two main parts to this pattern: [A-Z0-9]{7} to match a hyphen-free string and (?=^[^-]+-[^-]+$)[A-Z0-9-]{8} to match a hyphenated string.

The (?=^[^-]+-[^-]+$) will match for any string with a SINGLE hyphen in it (and the hyphen isn't the first or last character), then the [A-Z0-9-]{8} part will count the characters and make sure they are all valid.

Upvotes: 1

samg
samg

Reputation: 3526

I think this should do it:

/^[a-zA-Z0-9]{3}-?[a-zA-Z0-9]{4}$/

It matches 3 letters or numbers followed by an optional hyphen followed by 4 letters or numbers. This one works in ruby. Depending on the regex engine you're using you may need to alter it slightly.

Upvotes: 5

pcronin
pcronin

Reputation: 1109

Not sure if this counts, but I'd break it into two regexes:

#!/usr/bin/perl

use strict;
use warnings;

my $text = '333-URGE';

print "Format OK\n" if $text =~ m/^[\dA-Z]{1,6}-?[\dA-Z]{1,6}$/;
print "Length OK\n" if $text =~ m/^(?:[\dA-Z]{7}|[\dA-Z-]{8})$/;

This should avoid accepting multiple dashes, dashes in the wrong place, etc...

Upvotes: 1

sivabudh
sivabudh

Reputation: 32635

Thank you Heath Hunnicutt for his alternation operator answer as well as showing me an example.

Based on his advice, here's my answer:

[A-Z0-9]{7}|[A-Z0-9][A-Z0-9-]{7}

Note: I tested my regex here. (Just including this for reference)

Upvotes: 0

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