PHP正则表达式特殊字符

Question

I am facing difficulties to validate the below format. I want regular expression needs to be satisfied with the below condition.

$pattern = '/^\w[\w\s\.\%\-\(\)\[\]]*$/u';
$file_name = "(00)filename.jpg";
if(preg_match($pattern,$file_name)){
    echo "Pattern matched";
}else {
    echo "Pattern not matched";
}

I have tried several ways. But, the main problem is do not write the own pregmatch, instead need to modify the existing one which accepts the brackets().

Answer 1

So this should match (00)filename.jpg and does not, because your regex requires the string to ^\w start with a word-character. You can add optional parenthesized \w+ to the start:

^(?:\(\w+\)|\w)[-\w\s.%()[\]]*$

Also need to put the hyphen - at the start or end inside the character class. Else it would express a range. Furthermore need to escape the closing ] inside the character class.

test at regex101

---

But possibly, you just want to check:

• if there's at least one word-character in the string.
• the string consist only of [-\w\s.%()[\]]

If so, use a lookahead to check for the \w:

^(?=.*?\w)[-\w\s.%()[\]]+$

test at regex101