substr php removes the last character of the string and appends the usage of substr

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

Copy the code The code is as follows:

$str = "1,2,3,4,5,6,";
$newstr = substr($str,0, strlen($str)-1);
echo $newstr;

Interpretation:
Using PHP’s substr() method,
Syntax: string substr(string string, int start, int [length]);
Parameter 1: Original string;
Parameter 2: starting position of cutting;
Parameter 3: intercepted length;
Use as follows:
$newstr = substr($str,0,strlen($str)-1);
From Intercept from the beginning and continue to the penultimate digit, thus removing the last ",".
The system’s own functions can also achieve this effect, two methods:
1) substr($str, 0, -1)
2) rtrim($str, ",")
substr
Get part of the string .
Syntax: string substr(string string, int start, int [length]);
Return value: string
Function type: Data processing
Content description
This function takes out the length of the string starting from the start position of the string string characters. If start is a negative number, it starts from the end of the string. If the omitted parameter length exists but is a negative number, it means that the length character from the bottom is obtained.
Usage example

Copy code The code is as follows:

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
rtrim() function removes whitespace characters or other predefined characters from the end of a string. Same as chop() function.
Syntax

Parameters	Description
string	Required. Specifies the string to be converted.
charlist	Optional. Specifies which characters are removed from the string. If this parameter is not set, all the following characters will be deleted: " The above introduces the use of substr php to remove the last character of a string and append substr, including the content of substr. I hope it will be helpful to friends who are interested in PHP tutorials.