How to get the last digits of a string in php

Two methods: 1. Use the substr() function to intercept the last N digits of the English string. You only need to set the second parameter of the function to "-N" and omit the third parameter. Syntax "substr($str,-N)"; 2. Use the mb_substr() function to intercept the last N digits of the Chinese string. You only need to set the second parameter of the function to "-N" and the third parameter to N is enough, the syntax is "mb_substr($str,-N,N, character encoding)".

The operating environment of this tutorial: windows7 system, PHP8.1 version, DELL G3 computer

Method 1: Use substr() The function intercepts the last N digits of the English string

substr() function can intercept characters of a certain length from the specified position of the string.

substr(string,start,length)

Parameters	Description
string	Required . Specifies a part of the string to be returned.
start	Required. Specifies where in the string to begin. Positive number - starts at the specified position in the string Negative number - starts at the specified position from the end of the string 0 - at the first character in the string Start at
length	Optional. Specifies the length of the string to be returned. The default is until the end of the string. Positive number - Returns from the position of the start parameter Negative number - Returns from the end of the string

Just set the second parameter of the function to -N, and omit the third parameter to intercept the last N characters of the string.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str="Hello world";
echo "原字符串：".$str."<br>";
echo "截取后1位：".substr($str,-1)."<br>";
echo "截取后2位：".substr($str,-2)."<br>";
echo "截取后3位：".substr($str,-3)."<br>";
echo "截取后4位：".substr($str,-4)."<br>";
echo "截取后5位：".substr($str,-5)."<br>";
?>

Note: The substr() function has no problem processing English, but in development we often deal with more Chinese characters. Although the substr() function It can also handle Chinese, but it's not perfect.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str="欢迎来到PHP中文网";
echo "原字符串：".$str."<br>";
echo "截取后1位：".substr($str,-1)."<br>";
echo "截取后2位：".substr($str,-2)."<br>";
?>

So how to intercept Chinese characters? You can use the mb_substr() function.

Method 2: Use the mb_substr() function to intercept the last N digits of the Chinese string

The mb_substr() function can intercept a specified part from a string, and substr () function is that the mb_substr() function is not only valid for English characters, but also for Chinese characters.

mb_substr(string,start,length,encoding)

Required. Specifies where in the string to begin. Optional. Specifies the length of the string to be returned. The default is until the end of the string. encodingOptional. Character Encoding. If omitted, the internal character encoding is used.

Parameters	Description
str	Required . Extracts a substring from this string.
##start	Positive number - starts at the specified position in the string Negative number - starts at the specified position from the end of the string 0 - at the first character in the string Start at
length	Positive number - Returns from the position of the start parameter Negative number - Returns from the end of the string

You only need to set the second parameter of the function to

-N, and the third parameter to N, that is The last N characters of the string can be intercepted.

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str="欢迎来到PHP中文网";
echo "原字符串：".$str."<br>";
echo "截取后1位：".mb_substr($str,-1,1,"utf-8")."<br>";
echo "截取后2位：".mb_substr($str,-2,2,"utf-8")."<br>";
echo "截取后3位：".mb_substr($str,-3,3,"utf-8")."<br>";
echo "截取后4位：".mb_substr($str,-4,4,"utf-8")."<br>";
?>

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