PHP removes the usage of the last character substr () of the string

Used in today's project to remove the last character in the string
Original string 1, 2, 3, 4, 5, 6,
Remove the last character "," and the final result is 1, 2, 3, 4, 5, 6.
The Code is as follows:

$ STR = "1, 2, 3, 4, 5, 6 ,";
$ Newstr = substr ($ STR, 0, strlen ($ Str)-1 );
Echo $ newstr;

The built-in functions of the system can also achieve the following two methods:
1) substr ($ STR, 0,-1)
2) rtrim ($ STR ,",")

Substr

Take some strings.

Syntax:String substr (string, int start, int [length]);

Return Value: String

Function Type: Data Processing

Description

This function extracts the start character of the string from the start character. If start is a negative number, it is counted from the end of the string. If the parameter length can be omitted, but it is a negative number, it indicates that the maximum length is obtained.

Example

<?
Echo substr ("abcdef", 1, 3); // return "BCD"
Echo substr ("abcdef",-2); // return "Ef"
Echo substr ("abcdef",-3, 1); // return "D"
Echo substr ("abcdef", 1,-1); // return "bcde"
?>

PHP rtrim () function definition and usage

The rtrim () function removes white spaces or other predefined characters from the end of a string. The same as the chop () function.

Syntax

rtrim(string,charlist)

Parameters	Description
String	Required. Specifies the string to be converted.
Charlist	Optional. Specifies which characters are deleted from the string. If this parameter is not set, all of the following characters are deleted: "\ 0"-ASCII 0, null "\ T"-ASCII 9, Tab "\ N"-ASCII 10, New Line "\ X0b"-ASCII 11, vertical Tab "\ R"-ASCII 13, press ENTER ""-ASCII 32, space

Example