PHP replace string function example analysis

Through the replacement technology of string, the specified characters in the specified string can be replaced. String replacement technology can be implemented through the following two functions: str_irplace() function and substr_replace() function.

str_irplace() function

Use a new string (substring) to replace the specified string to be replaced in the original string .

The syntax format is as follows:

str_irplace(search, replace, subject, count)

Instructions: Replace all the parameter subject that appears in the parameter subject with the parameter replace, and the parameter count represents the number of times the replacement string is executed. The str_irplace() function is not case sensitive.

##parameter numbersay 明search Required parameters, specify the string to be found#replaceRequired parameters, specify the value to be replacedsubjectRequired parameters, specify the range to be searchedcountOptional parameters, get the number of times to perform replacementReplace the string specified in the text, and then output the replaced result. The example code is as follows:

<?php
$str = "看国足打比赛就像单恋一个不爱你的人，Ta稍微给你一点好脸色，你就以为有戏了。";
$str1 = "**";
$str2 = "国足";
echo str_ireplace($str2,$str1,$str);    //输出替换后的字符串
?>

The output result is:

Watching ** play a game is like having unrequited love for someone who doesn't love you. If he gives you a little bit of a good look, you think it's okay.

Note: This function is not case-sensitive when performing the replacement operation. If you need to distinguish between upper and lower case, you can use the str_replace() function.

The most commonly used string replacement technology is in the keyword processing of

search engines. String replacement technology can be used to replace the keywords of the searched string with colors, such as query Keyword red marking function makes the search results easier for users to view.

Note: Marking the query keywords in red means marking the query keywords in a special color, font size or font. This allows the viewer to quickly find the required keywords and facilitates the viewer to select from the search results. Find what you need. Query keywords marked in red are suitable for fuzzy queries.

The following uses a specific example to introduce how to implement the red marking function of query keywords.

Use the str_irplace() function to replace the query keyword. When the relevant information being queried is displayed, replace the font of the output keyword with red. The sample code is as follows:

<?php
$content = "看国足打比赛就像单恋一个不爱你的人，Ta稍微给你一点好脸色，你就以为有戏了";
$str = "国足";
echo str_ireplace($str,"<font color=&#39;red&#39;>$str</font>",$content);    //替换字符串为红色字体
?>

The output result is:

WatchNational Football TeamPlaying a game is like having unrequited love for someone who doesn’t love you. If he gives you a little bit of a good look, you I thought it was going to work

Note: The query keyword red function is widely used in search engines. I hope that friends can learn from examples and draw inferences to develop more flexible and convenient programs.

substr_replace() function

Replaces part of the string in the specified string.

The syntax format is as follows:

substr_replace(string, replacement, start, length)

The parameter description is as follows:

##Parameter Numberstring replacementstartlength

说明：start参数为正数表示起始位置从字符串开头开始；负数表示起始位置从字符串的结尾开始； 0表示起始位置字符串中的第一个字符。

length参数默认值是整个字符串。正数表示起始位置从字符串开头开始；负数表示起始位置从字符串的结尾开始；0表示插入而非替代。

注意： 如果start参数设置为负数，而参数length数值小于或者等于start参数，那么length值自动为0。

使用substr_replace()函数对指定字符串进行替换，示例如下所示：

<?php
$str = "用今日的努力工作，换明日的双倍回报！";
$replace = "十倍";                               //定义要替换的字符串
echo substr_replace($str,$replace,39,6);         //替换字符串
?>

输出结果为：用今日的努力工作，换明日的十倍回报！

说明：在上面的代码中，主要是用substr_replace()函数实现将字符串 “双倍” 替换为字符串 “十倍”。

Description
Specify the original string that needs to be operated
Specifies the new string after replacement
Specifies the starting position of the replacement string
Optional parameter, specify the replacement string length

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