PHP 5.5.20 is available

Validation

Example #1 Validating email addresses with filter_var()

<?php
$email_a 
'joe@example.com';
$email_b 'bogus';

if (
filter_var($email_aFILTER_VALIDATE_EMAIL)) {
    echo 
"This ($email_a) email address is considered valid.";
}
if (
filter_var($email_bFILTER_VALIDATE_EMAIL)) {
    echo 
"This ($email_b) email address is considered valid.";
}
?>

The above example will output:

This (joe@example.com) email address is considered valid.

Example #2 Validating IP addresses with filter_var()

<?php
$ip_a 
'127.0.0.1';
$ip_b '42.42';

if (
filter_var($ip_aFILTER_VALIDATE_IP)) {
    echo 
"This (ip_a) IP address is considered valid.";
}
if (
filter_var($ip_bFILTER_VALIDATE_IP)) {
    echo 
"This (ip_b) IP address is considered valid.";
}
?>

The above example will output:

This (ip_a) IP address is considered valid.

Example #3 Passing options to filter_var()

<?php
$int_a 
'1';
$int_b '-1';
$int_c '4';
$options = array(
    
'options' => array(
                      
'min_range' => 0,
                      
'max_range' => 3,
                      )
);
if (
filter_var($int_aFILTER_VALIDATE_INT$options) !== FALSE) {
    echo 
"This (int_a) integer is considered valid (between 0 and 3).\n";
}
if (
filter_var($int_bFILTER_VALIDATE_INT$options) !== FALSE) {
    echo 
"This (int_b) integer is considered valid (between 0 and 3).\n";
}
if (
filter_var($int_cFILTER_VALIDATE_INT$options) !== FALSE) {
    echo 
"This (int_c) integer is considered valid (between 0 and 3).\n";
}

$options['options']['default'] = 1;
if ((
$int_c filter_var($int_cFILTER_VALIDATE_INT$options)) !== FALSE) {
    echo 
"This (int_c) integer is considered valid (between 0 and 3) and is $int_c.";
}
?>

The above example will output:

This (int_a) integer is considered valid (between 0 and 3).
This (int_c) integer is considered valid (between 0 and 3) and is 1.

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User Contributed Notes 3 notes

up
-17
makicar5 at gmail dot com
10 months ago
Email example is correct, in other examples just add dollar sign:

echo "This (ip_a) IP address is considered valid.";
echo "This (ip_a) IP address is considered valid.";

Change to:

echo "This ($ip_a) IP address is considered valid.";
echo "This ($ip_a) IP address is considered valid.";

same for
int_a, int_b, int_c 
to $int_a, $int_b, $int_c

Don't use single quotes in this example!
up
-28
brokendocs at php dot net
1 year ago
all the above documentation is slightly incorrect, the output is not reading the variables in -

code:

$email_a = 'joe@example.com';
$email_b = 'bogus';

if (filter_var($email_a, FILTER_VALIDATE_EMAIL)) {
    echo "This ($email_a) email address is considered valid.";
}

output:

This (email_a) email address is considered valid.

should be output:

This (joe@example.com) email address is considered valid.

same for the IP and integer examples.
up
-29
Stan
1 year ago
HP 5.3.3 and 5.2.14 had a bug (http://bugs.php.net/52929) related to FILTER_VALIDATE_EMAIL, which resulted in segfault when validating large values. Simple and safe workaround for this is using strlen() before filter_val(). I'm not sure about 5.3.4 final, but it is written that some 5.3.4-snapshot versions also were affected.

Originally posted here - http://stackoverflow.com/questions/5855811/how-to-validate-an-email-in-php#comment6729146_5855853.
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