4 situations in which php removes spaces and special characters from text

In daily development, when processing some submitted content, it is often necessary to consider the blank content. Because if there are gaps in the submitted data, it will cause problems for the program. For example, when a user fills in their email address and accidentally adds spaces at the end or beginning, the email address submitted by the user will be incorrect. In order to avoid this situation, we It is necessary to remove the spaces from the data submitted by the user. In this chapter, I will introduce you to several methods on how to remove spaces?

Recommended manual

: php complete self-study manual

First method: remove the spaces on the left and right sides.

The trim() function is provided in PHP to remove spaces and special characters on the left and right sides of a string.

The syntax of the trim() function is as follows

trim(string,charlist)

The parameter string of the trim() function specifies the string to be checked. The charlist parameter specifies those special characters that need to be removed from the string, such as spaces, carriage returns, etc. If this parameter is not set, all special characters will be removed by default. The optional values ​​​​of the charlist parameter are as follows:

Parameter valueDescription\ 0\ttab character\n\x0B##\ rEnterSpaceIn addition to the above In addition to the default filter character list, you can also provide special characters to be filtered in the charlist parameter

NULL, empty value
tab,
Line break
Vertical tab
	##" "

Example

Remove spaces on both sides of the string:

<?php
header("content-type:text/html;charset=utf-8");
$str = "            Hello World!           ";
echo "不使用 trim: " . $str;
echo "<br>";
echo "使用 trim: " . trim($str);
?>

Running results View the source code results as shown below

Recommended related articles:

1.

How to replace spaces in php ( Code) 2.
How does PHP filter spaces in strings
Related video recommendations:1.
Dugu Jiujian(4 )_PHP video tutorial
Second type: remove the spaces on the left

ltrim() function removes the blank characters on the left side of the string or Other predefined characters. The syntax is as follows

ltrim(string,charlist)

The parameter string of the ltrim function specifies the string to be checked, and the charlist parameter specifies the special characters that need to be removed from the string. Like the trim() function, the optional values ​​​​of the charlist parameter are as follows Table:

Parameter valueNULL, empty value tab, tab characterLine breakVertical tabEnter##" "Space

实例

移除字符串左侧的空格：

<?php
header("content-type:text/html;charset=utf-8");
$str = "    PHP中文网";
echo "不使用 ltrim: " . $str;
echo "<br>";
echo "使用 ltrim: " . ltrim($str);
?>

运行结果查看源码结果如下图

第三种：去除右边的空格

rtrim() 函数移除字符串右侧的空白字符或其他预定义字符。语法如下

rtrim(string,charlist)

rtrim()函数的参数string是规定要检查的字符串，charlist参数是指定需要从字符串中去除那些特殊字符，与trim()和ltrim()函数一样，charlist参数的可选值如下表：

Description	\0
	\t
	\n
	\x0B
	\r

参数值	说明
\0	NULL，空值
\t	tab，制表符
\n	换行
\x0B	垂直制表符
\r	回车
" "	空格

实例

移除字符串右侧的空格：

<?php
header("content-type:text/html;charset=utf-8");
$str = "PHP中文网    ";
echo "不使用 rtrim：" . $str;
echo "<br>";
echo "使用 rtrim：" . rtrim($str);
?>

运行结果查看源码结果如下图

第四种：去除所有的空格或特殊字符

str_replace() 函数以其他字符替换字符串中的一些字符（区分大小写）。str_replace() 函数是已替换的方式将字符串中的空格或特殊字符替换掉自己想要的，语法如下：

str_replace(find,replace,string,count)

参数详解：

find    必需。规定要查找的值。    
replace    必需。规定替换 find 中的值的值。    
string    必需。规定被搜索的字符串。    
count    可选。对替换数进行计数的变量。

实例

去除所有的空格

<?php
header("content-type:text/html;charset=utf-8");
$str = "      PHP     中     文   网    ";
echo $str."<br/>";
$re=str_replace(" ",&#39;&#39;,$str);
echo $re
?>

运行结果如下：

去除各种空格的几种方法已经给大家介绍了，希望对大家有所帮助.

The above is the detailed content of 4 situations in which php removes spaces and special characters from text. For more information, please follow other related articles on the PHP Chinese website!