How to Remove Predefined Characters From the End of a String In PHP?

SOLUTION: Learn how to remove predefined characters from the end of a string in PHP

Problem:

You told users not to add any number at the end in a form field. But, few users mistakenly did that. Now, you need a way to remove those numbers and get the remaining characters.

Solution:

Use chop() function in php

Example:

 <?php
$user_input = “Thank you123”;
echo chop($user_input, “0..9”);
?>

Output:
Thank you

How it works:

chop() function can take two parameters and it removes second parameter(here 0..9) from the end of the first parameter. As there is 123 at the end of Thank you123, so it removes 123 and returns the “Thank you” only.

To indicate a range ..(double dot) is used. Instead of 0..9, 0123456789 can be used. It will work the same.

Caution 1: Characters in the parameters are case sensitive. In the following example, the capital letter Y in the first parameter will not be removed. By indicating small letters (a..z) in the second parameter, the function tells to remove only the small letters at the end of the first parameter.

Example:

 <?php
$user_input = “Thank You”;
echo chop($user_input, “a..z”);
?>

Output:
Thank Y

Caution 2: The function removes characters from the end of the first parameter as long as it finds any unmatched character. So, it will not remove other matching characters that exist before that unmatched character.

Example:

<?php
$user_input = “Thank You”;
echo chop($user_input, “a..z”);
?>

Output:
Thank Y

In the above example, though there are small letters (hnak) exist before Y, but, it is not removed as capital Y is not told to remove and it stops there.


chop() function at a glance

(PHP4, PHP5)

Usages:
chop() function is used to remove trailing spaces or any predefined character(s) at the end of a string.

Syntax:
chop(string, charlist)

Parameters:

Parameter What it does
string Required Define the string to check
charlist Optional Specify which characters to remove from the string

With or without the optional parameter

Function 1st parameter 2nd parameter What it does Example
chop(string) green-tick  green-tick Without 2nd parameter, the following characters are removed  at the end of string(1st parameter)

  • ” ” -  an ordinary white space
  • “\t” – tab.
  • “\n” -new line
  • “\r” -  carriage return
  • “\0″ -  NULL

“\x0B” – vertical tab.

chop(“Morning ”)
Output: Morning
(Note: In the output, there is no space after the word Morning)
Chop(string, charlist) green-tick green-tick It removes charlist at the end of string chop(“Hello World”, “World”)
Output: Hello


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