I have a strange question maybe you could help me with. I am trying to check whether the given string contains special characters. The code below is working however one character seems to get exempted on the condition which is the square brackets [ ]. Can you help me with this? thank you.
$string = 'starw]ars';
if (preg_match('/[\'^£$%&*()}{##~?><>,|=_+¬-]/', $string)) {
echo 'Output: Contains Special Characters';
}else{
echo 'Output: valid characters';
}
Please note: I can't use below condition since I need to accept others characters from other languages like in arabic, chinese, etc. so it means I need to specify all characters that is not allowed.
if (!preg_match('/[^A-Za-z0-9]/', $string))
Appreciate your help. Thanks.
You forgot to add square brackets [] in your expression. I have added this \[\] in your current expression.
Try this code snippet here
<?php
ini_set('display_errors', 1);
$string = 'starw]ars';
if (preg_match('/[\[\]\'^£$%&*()}{##~?><>,|=_+¬-]/', $string))
{
echo 'Output: Contains Special Characters';
} else
{
echo 'Output: valid characters';
}
Use strpos:
$string = 'starw]ars';
if (strpos($string, ']') !== false) {
echo 'true';
}
Please see the following answer for additional information:
How do I check if a string contains a specific word in PHP?
You should add escaped square brackets to your expression.
preg_match('/[\'^£$%&*()}{##~?><>,|=_+¬-\[\]]/', $string)
EDIT: Apologies to #Thamilan, I didn't see your comment.
EDIT 2: You could also use the preg_quote function.
preg_match(preg_quote('\'^£$%&*()}{##~?><>,|=_+¬-[]', '/'), $string);
The preg_quote function will escape your special characters for you.
Try this example:
<?php
$string = 'starw]]$%ars';
if (preg_match('/[\'\/~`\!##\$%\^&\*\(\)_\-\+=\{\}\[\]\|;:"\<\>,\.\?\\\]/', $string))
{
echo 'Output: Contains Special Characters';
} else
{
echo 'Output: valid characters';
}
?>
Output:
Output: Contains Special Characters
Related
I would like to validate a string with a pattern that can only contain letters (including letters with accents). Here is the code I use and it always returns "nok".
I don't know what I am doing wrong, can you help? thanks
$string = 'é';
if(preg_match('/^[\p{L}]+$/i', $string)){
echo 'ok';
} else{
echo 'nok';
}
Add the UTF-8 modifier flag (u) to your expression:
/^\p{L}+$/ui
There is also no need to wrap \p{L} inside of a character class.
I don't know if this helps anybody that will check this question / thread later. The code below allows only letters, accents and spaces. No symbols or punctuation like .,?/>[-< etc.
<?php
$string = 'États unis and états unis';
if(preg_match('/^[a-zA-Z \p{L}]+$/ui', $string)){
echo 'ok';
} else{
echo 'nok';
}
?>
If you want to add numbers too, just add 0-9 immediately after Z like this a-zA-Z0-9
Then if you are applying this to form validation and you are scared a client/user might just hit spacebar and submit, just use:
if (trim($_POST['forminput']) == "") {... some error message ...}
to reject the submission.
I am trying to find if a persons name contains any numbers or symbols. I am not very sure how to use preg_match and all the examples online make no sense can someone please explain how i can check if a value has numbers or symbols. And if you can please explain how it works.
To check if the person name contains only number. The code below has been tested and is working
<?php
error_reporting(0);
$number = '001222288';
if (!preg_match('/^[0-9]*$/', $number)) {
//error
echo 'Error does not contain only number';
} else {
echo 'success. it contains only number';
}
?>
if the variable number contains any other thing that is not number it result in error. eg
$number = 'ABFRT001222288';
To check for alphabets or string
<?php
error_reporting(0);
$string = 'ABTYUUU';
if (!preg_match('/^[A-Z]*$/', $string)) {
//error
echo 'Error does not contain only alphabet';
} else {
echo 'success. it contains only alphabets';
}
?>
Mark this as correct answer if it solve your problem
Thanks
The function preg_match use regex expressions. You can use an online tool for test your regex. I use debuggex, preg_match use PCRE expressions. In your case you should, you may use for numbers
preg_match("/[0-9]+/", $subject);
EDIT : We need more details for the symbols you want select
How to match any thing dosen't contain a specific word using RegExp
Ex:
Match any string doesn't contain 'aabbcc'
bbbaaaassdd // Match this
aabbaabbccaass // Reject this
If you're just after this sequence of characters, don't use a Regular Expression. Use strpos().
if (strpos('aabbaabbccaass', 'aabbcc') !== false) {
echo 'Reject this.'
}
Note: Be sure to read the warning in the manual about strpos() return values.
You can use negative lookahead:
(?!.*?aabbcc)^.*$
Live Demo: http://www.rubular.com/r/4Exbf7UdDv
PHP Code:
$str = 'aabbaabbccaass'; //or whatever
if (preg_match('/(?!.*?aabbcc)^.*$/', $str))
echo "accepted\n";
else
echo "rejected\n";
try this to avoid some sequences of letters :
^((?!aabbcc).)*$
try this:
if(preg_match('/aabbcc/', $string) == 0) {
[ OK ]
}
else {
[ NOT OK ]
}
You can use this to describe a substring that doesn't contain aabbcc:
(?>[^a]++|a(?!abbcc))*
for the whole string, just add anchors (^ $)
I would like to validate a string with a pattern that can only contain letters (including letters with accents). Here is the code I use and it always returns "nok".
I don't know what I am doing wrong, can you help? thanks
$string = 'é';
if(preg_match('/^[\p{L}]+$/i', $string)){
echo 'ok';
} else{
echo 'nok';
}
Add the UTF-8 modifier flag (u) to your expression:
/^\p{L}+$/ui
There is also no need to wrap \p{L} inside of a character class.
I don't know if this helps anybody that will check this question / thread later. The code below allows only letters, accents and spaces. No symbols or punctuation like .,?/>[-< etc.
<?php
$string = 'États unis and états unis';
if(preg_match('/^[a-zA-Z \p{L}]+$/ui', $string)){
echo 'ok';
} else{
echo 'nok';
}
?>
If you want to add numbers too, just add 0-9 immediately after Z like this a-zA-Z0-9
Then if you are applying this to form validation and you are scared a client/user might just hit spacebar and submit, just use:
if (trim($_POST['forminput']) == "") {... some error message ...}
to reject the submission.
I'm trying to find special characters with characters like <?, <?php, or ?> in a string. The code below works to find "php" in the string anywhere no matter if it's PHP, php, or phpaPHPa.
<?php
$searchfor = "php";
$string = "PHP is the web scripting language of choice.";
if (preg_match("/".$searchfor."/i", $string)) {
echo "A match was found.";
} else {
echo "A match was not found.";
}
?>
I need a similar code that finds special characters like <?, <?php, or ?> in the string. Any suggestions?
You can use same code. Just make sure to escape regex special characters when using them in matching. The question mark must be escaped so your $searchfor becomes <\?php
Using strpos (or stripos) will be faster than using RegEx'es...
if(false === strpos($text, '<?'))
echo 'Match was not found';
else
echo 'Match was found';