How to implement flip in php

How to implement flipping in php: 1. Use the strrev() function to flip English strings; 2. Use the customized selfStrrev method to flip Chinese strings.

#The operating environment of this article: Windows 7 system, PHP version 7.1, Dell G3 computer.

How to implement flipping in php? PHP custom function realizes the function of flipping Chinese

For PHP language, when it comes to string flipping, the first thing that everyone thinks of is the strrev() function,

strrev definition and usage

strrev() function reverses a string.

Syntax

strrev(string)

Parameters

string Required. Specifies the string to reverse.

For example:

<?php
echo strrev("Hello World!");
?>

The output result is: !dlroW olleH

strrev() This function is very useful for English. It can directly realize string flipping, but if it is Chinese If so, then it will all be garbled characters

For example:

<?php
echo strrev("您好世界!");
?>

The output result is: ��疸佥娂� Is this result something that no one can understand? So below, Teacher Yu will share with you how to reverse the Chinese code;

The first method:

function selfStrrev($str){
//判断输入的是不是utf8类型的字符，否则退出
  if(!is_string($str)||!mb_check_encoding($str,'UTF-8')){
    exit("输入类型不是UTF8类型的字符串");
  }
  $array=array();
  //将字符串存入数组
  $l=mb_strlen($str,'UTF-8');//在mb_strlen计算时，选定内码为UTF8，则会将一个中文字符当作长度1来计算
  for($i=0;$i<$l;$i++){
    $array[]=mb_substr($str,$i,1,&#39;UTF-8&#39;);
  }
  //反转字符串
  krsort($array);
  //拼接字符串
  $string=implode($array);
  return $string;
}
$str = "于老师特别帅";
echo selfStrrev($str);

The output result is: Shuai Bie Special Teacher Yu ;

Second method:

function selfStrrev($str){
//判断输入的是不是utf8类型的字符，否则退出
  if(!is_string($str)||!mb_check_encoding($str,'UTF-8')){
    exit("输入类型不是UTF8类型的字符串");
  }
  //定义一个新的字符串 用来存储反转后的字符串
  $revStr = "";
  $l=mb_strlen($str,'UTF-8');//在mb_strlen计算时，选定内码为UTF8，则会将一个中文字符当作长度1来计算
  for($i=$l;$i>0;$i--){
    $revStr .= mb_substr($str,$i-1,1,'UTF-8'); //从最后一位开始截取，一直截取到第一位 然后拼接到定义好的新的字符串里面
  }
  return $revStr;
}
$str = "于老师特别帅";
echo selfStrrev($str);

The output result is: Shuai Bie Te Shi Lao Yu;

The technology used here is the mb_XXX series Functions, it should be noted that the mb_XXX series of functions are not PHP core functions. Before use, you need to make sure that php_mbstring.dll is loaded in php.ini, that is, make sure that the line "extension=php_mbstring.dll" exists and has not been commented out, otherwise it will The problem of undefined function occurs;

Recommended study: "PHP Video Tutorial"

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