PHP string flip instance code

 

Character flip is a piece of cake for php processing. php's string function strrev can handle the following:

 

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