PHP string flip instance code _ PHP Tutorial

PHP string flip instance code. Character flip is a piece of cake for php processing. php's string function strrev can be used for processing, for example, echostrrev (HelloWorld !); The output result is! DlroWolleH is a piece of cake for php processing, but sometimes the interview character is flipped. the strrev function of php can be processed as follows:

Echo strrev ("Hello World! "); // The output result is "! DlroW olleH"

However, sometimes during interviews, we often need to write a function to achieve the same effect as strrev. In fact, this is not difficult, for example:

/**

* String flip function

* @ Param string $ str the string to be processed

* @ Return string that is successfully flipped

*/

Function reverse ($ str ){

If ($ str = ''){

Return null;

}

If (strlen ($ str) = 1 ){

Return $ str;

} Else {

$ String = "";

For ($ I = 1; $ I <= strlen ($ str); $ I ++ ){

$ String. = substr ($ str,-$ I, 1 );

}

Return $ string;

}

}

Echo reverse ("Hello World! "); // The output result is "! DlroW olleH"

From: Shine's holy heaven

Repeated echo strrev (Hello World !); // The output result is! DlroW olleH but sometimes interviews...