检查字符串是否包含空格，下划线和字符

Question

i want to check if string has other than spaces,underscore,digit and character.

i have created the following code.But this is not working when i add any other special character or hyphen.

For example take this string.Now this is not valid.when i remove #%#% from string valid.

$string = 'a1uper___ w__#%#%';
if(preg_match('/[a-zA-Z_]/',$string)){      
   echo 'valid';
 }
 else{
   echo 'not valid';
}

I have tried the following pattern also:

'/[a-zA-Z_]/'
'/^[a-zA-Z_]/'
'/[a-z][A-Z][_]/',...

please help

Answer 1

You need to do it like below:-

<?php

$string = 'a1uper___ w__ ';

if(preg_match('/^[a-zA-Z_\/\s\d]+$/i',$string)){      
    echo 'valid';
}
else{
    echo 'not valid';
}

Output:- https://eval.in/806911

Note:-

a-zA-Z    is for characters
_         for underscores
/s        for spaces
d         for digits

Now '/^[a-zA-Z_\/\s\d]+$/i' will check that string doesn't contain anything apart from the above mentioned.

If string have above mentioned things only then valid otherwise invalid.

That's why:-

a1uper___ w__ is valid (only characters and underscores are there)

a1uper___ w__#%#% is invalid (because of having unmatched characters #%#% )

Reference:-

1. https://regex101.com/

2. http://www.phpliveregex.com/

3. https://www.functions-online.com/preg_match.html