Definition and syntax of removing null characters in php trim

Definition and usage
The trim () function removes spaces and other predefined characters from both ends of the string.

Syntax
Trim (string, charlist) parameter description

String is required. Specifies the string to be checked.

Charlist is optional. Specifies the string to be converted. If this parameter is omitted, all the following characters are deleted:

Copy codeThe Code is as follows: "\ 0"-NULL
"\ T"-tab
"\ N"-new line
"\ X0B"-vertical list Operator
"\ R"-press ENTER
""-General white space characters

Example 1 Copy codeThe Code is as follows: <? Php
$ Str = "Remove blank characters at both ends of the string using the trim function ";
$ Str1 = trim ($ str); echo "before processing". strlen ($ str). "characters ";
Echo "<br/> ";
Echo "<br/> ";
Echo "after processing with the trim function". strlen ($ str1). "characters ";
?>

Output:

39 characters before processing 34 characters after being processed using the PHP function trim ()

Example 2
Copy codeThe Code is as follows: <? Php
$ Str = "## remove specific characters at both ends of the string using the trim function ####";
$ Str1 = trim ($ str, "#"); // input the second parameter for the trim function. trim deletes the # characters at both ends of the string $ str.
Echo $ str. "<br> ";
Echo $ str1;
?>

Output:
# Use the PHP function trim () to remove specific characters at both ends of the string ### use the function trim to remove specific characters at both ends of the string