How to remove the first character from a php string

3 methods: 1. Use substr_replace() to replace the first character with a null character, the syntax is "substr_replace($str,'',0,1)"; 2. Use substr() to replace the first character with a null character. Start intercepting all the remaining characters from 2 characters, the syntax is "substr($str,1)"; 3. Use mb_substr() to intercept all the remaining characters starting from the 2nd character, the syntax is "mb_substr($str,1, the remaining The number of characters, "character encoding")".

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

Remove the php string 3 methods for the first character

Method 1: Use the substr_replace() function to replace the first character of the string with an empty character

## The #substr_replace() function can replace the specified number of characters starting from the specified position in the string.

If you want to replace the first character of the string with a null character, you only need to set the second parameter to the null character "

''" and the third parameter to "0", the fourth parameter can be set to 1. (The index of characters in the string starts with 0, so the starting position of the first character is 0)

Example:

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str = &#39;hello world!&#39;;
echo "原字符串：".$str."<br><br>";
$replace = &#39;&#39;;
echo "删除第一位字符：".substr_replace($str, $replace,0,1)."<br>";
?>

Method 2: Use the substr function to intercept all remaining characters starting from the second character of the string

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

You only need to set the second parameter of the function to 1 and omit the third parameter.

Example:

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$str="Hello world";
echo "原字符串：".$str."<br>";
echo "删除第一位字符：".substr($str,1);
?>

Note: The substr() function has no problem processing English, but in development we often deal with Chinese characters More generally, although the substr() function can also handle Chinese, it is 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 "删除第一位字符：".substr($str,1);
?>

At this time, you need to use the mb_substr() function.

Method 3: Use the mb_substr() function to intercept all the remaining characters starting from the second character of the string

The mb_substr() function can also be used to intercept the remaining characters from the string. Intercept characters of a certain length at the specified position; and the mb_substr() function is not only valid for English characters, but also for Chinese characters.

<?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 "删除第一位字符：".mb_substr($str,1,mb_strlen($str)-3,"utf-8");
?>

Description: Function used

1, substr_replace() function

substr_replace() function replaces part of a string with another string.

substr_replace(string,replacement,start,length)

• substr_replace() Replaces the substring qualified by the start and optional length parameters with replacement in a copy of string string.

• If start is a positive number, replacement will start from the start position of string. If start is negative, the replacement will start at the start position from the bottom of string.

• If the length parameter is set and is a positive number, it represents the length of the replaced substring in string. If set to a negative number, it represents the number of characters from the end of the substring to be replaced from the end of string. If this parameter is not provided, the default is strlen(string) (the length of the string). Of course, if length is 0, then the function of this function is to insert replacement at the start position of string.

ParametersDescriptionRequired. Specifies the string to check. Required. Specifies the string to be inserted. Required. Specifies where in the string to begin replacement. Optional. Specifies how many characters to replace. The default is the same as the string length.

2、substr() 函数

substr() 函数返回字符串的一部分。

注释：如果 start 参数是负数且 length 小于或等于 start，则 length 为 0。

语法：

substr(string,start,length)

string
replacement
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 - the length of the string to be replaced Negative number - the number of characters to be replaced from the end of the string 0 - insert instead of replace

参数	描述
string	必需。规定要返回其中一部分的字符串。
start	必需。规定在字符串的何处开始。 正数 - 在字符串的指定位置开始 负数 - 在从字符串结尾的指定位置开始 0 - 在字符串中的第一个字符处开始
length	可选。规定要返回的字符串长度。默认是直到字符串的结尾。 正数 - 从 start 参数所在的位置返回 负数 - 从字符串末端返回

返回值：返回字符串的提取部分，如果失败则返回 FALSE，或者返回一个空字符串。  

3、mb_substr()函数

mb_substr() 函数可以从一个字符串中截取指定的一部分，与 substr() 函数不同的是，mb_substr() 函数不仅对英文字符有效，对中文字符同样有效。

mb_substr(string,start,length,encoding)

参数	描述
str	必需。从该 string 中提取子字符串。
start	必需。规定在字符串的何处开始。 正数 - 在字符串的指定位置开始 负数 - 在从字符串结尾的指定位置开始 0 - 在字符串中的第一个字符处开始
length	可选。规定要返回的字符串长度。默认是直到字符串的结尾。 正数 - 从 start 参数所在的位置返回 负数 - 从字符串末端返回
encoding	可选。字符编码。如果省略，则使用内部字符编码。

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