CODEWITHSUNDEEP
phpregex
coderex
coderex

Reputation: 27855

php regular expression to check whether a number consists of 5 digits

how to write a regular expression to check whether a number is consisting only of 5 digits?

Upvotes: 4

Views: 19592

Answers (4)

Jamol
Jamol

Reputation: 2291

Although not using regexp, but hopefully faster:

$var = trim($var);

if(strlen($var) == 5 && ctype_digit($var))
{
//
}

EDIT: Added trim function. It's important! It removes spaces so that strlen() function works as expected. Also it makes sure $var is a STRING. You need to pass a string to ctype_digit. If you pass say, an integer it will return false!!!

Upvotes: 4

Andrew Moore
Andrew Moore

Reputation: 95344

This regular expression should work nicely:

/^\d{5}$/

This will check if a string consists of only 5 numbers.

  • / is the delimiter. It is at the beginning and the end of a regular expression. (User-defined, you can use any character as delimiter).

  • ^ is a start of string anchor.

  • \d is a shorthand for [0-9], which is a character class matching only digits.

  • {5} means repeat the last group or character 5 times.

  • $ is the end of string anchor.

  • / is the closing delimiter.

If you want to make sure that the number doesn't start with 0, you can use the following variant:

/^[1-9]\d{4}$/

Where:

  • / is the delimiter. It is at the beginning and the end of a regular expression. (User-defined, you can use any character as delimiter).

  • ^ is a start of string anchor.

  • [1-9] is a character class matching digits ranging from 1 to 9.

  • \d is a shorthand for [0-9], which is a character class matching only digits.

  • {4} means repeat the last group or character 4 times.

  • $ is the end of string anchor.

  • / is the closing delimiter.

Note that using regular expressions for this kind of validation is far from being ideal.

Upvotes: 22

too much php
too much php

Reputation: 91028

This regex will make sure the number does not start with zeros:

if(preg_match('/^[1-9]\d{4}$/', $number))
    echo "Number is 5 digits\n";
else
    echo "Number is not five digits\n";

But why not use is_numeric() instead?

if(is_numeric($number) && $number >= 10000 && $number <= 99999)
    echo "Number is 5 digits\n";
else
    echo "Number is not five digits\n";

Or you can even just cast it to an integer to make sure it only has an integer value:

if(strval(intval($number)) === "$number" && $number >= 10000 && $number <= 99999)
    echo "Number is 5 digits\n";
else
    echo "Number is not five digits\n";

Upvotes: 14

Gumbo
Gumbo

Reputation: 655269

Try this:

^[0-9]{5}$

The ^ and $ mark the begin and end of the string where the characters described by [0-9] must be repeated 5 times. So this only matches numbers with exactly 5 digits (but it can still be 00000). If you want to allow only numbers from 10000 to 99999:

^[1-9][0-9]{4}$

And if you want to allow any number up to 5 digits (0 to 99999):

^(?:0|[1-9][0-9]{0,4})$

The (?:expr) is just a non-capturing grouping used for the alternation between zero and the other numbers with a non-zero leading digit.

Upvotes: 7

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