我试图删除特殊字符，但保留空格和_不工作PHP

Question

This is my code. I am using regex to check when creating a folder it does not contain special characters but allow spaces and underscores in the name. This code does not work but i cannot find the reason why. Please help me

if (preg_replace("/[^\w ]+/", "", $filename))
{
  echo 'A file name can not contain The Following Characters: \ / : * ? " < > | %';
}else{
  // do something
}

Answer 1

With preg_replace you replace the instances with something, from the php.net documentation :

preg_replace() : Searches subject for matches to pattern and replaces them with replacement.

You want the preg_match function which returns a boolean on if there was a match.

preg_match() : Searches subject for a match to the regular expression given in pattern.

Answer 2

Your using preg_replace you should be using preg_match

preg_replace will return the string which will always be true, unless everything has been removed

Answer 3

You can also use strpbrk() to search a string for any of a set of characters.

if (strpbrk($directoryName, "\\/?%*:|\"<> ") === FALSE) {
    /* $directoryName is legal; doesn't contain illegal character. */
}
else {
    /* $directoryName contains at least one illegal character. */
}

Answer 4

简单地使用

preg_replace('/[^a-zA-Z0-9%\[\]\.\(\)%&-]/s', '', $Your_String);