php 在不使用任何字符串函数的情况下反转php中的字符串
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Reverse a string in php without using any string function
提问by Shakun Chaudhary
In yesterday Interview I was asked that how to reverse a string with out using any string function like strrev() or strlen(). I found this example on website but it gives error.is it possible to do this without strlen().
在昨天的采访中，我被问到如何在不使用任何字符串函数（如 strrev() 或 strlen()）的情况下反转字符串。我在网站上找到了这个例子，但它给出了错误。是否可以在没有 strlen() 的情况下做到这一点。
Uninitialized string offset: -1 in D:\xampp\htdocs\PhpProject1\index.php on line xx
未初始化的字符串偏移量：-1 in D:\xampp\htdocs\PhpProject1\index.php on line xx
$string = "ZEESHAN";
$i =0;
while(($string[$i])!=null){
$i++;
}
$i--;
while(($string[$i])!=null){
echo $string[$i];
$i--;
}
回答by Surace
$string = 'zeeshan';
$reverse = '';
$i = 0;
while(!empty($string[$i])){
$reverse = $string[$i].$reverse;
$i++;
}
echo $reverse;
回答by Ashu Jha
I have created a simple logic for string reversal
我为字符串反转创建了一个简单的逻辑
$str = 'ABCD';
$strReversed = '';
$length = strlen($str);
for($i=$length-1; $i >= 0; $i--){
$strReversed .= $str[$i];
}
echo $strReversed;
回答by Sougata Bose
Try -
尝试 -
$string = "ZEESHAN";
$j = 0;
while(!empty($string[$j])) {
$j++;
}
for($i = ($j-1); $i >= 0; $i--) {
echo $string[$i];
}
Output
输出
NAHSEEZ
回答by Miguel
You can do this
你可以这样做
$string = "heya";
$i = strlen("heya") - 1;
$newStr = "";
while($i >= 0) {
$newStr .= $string[$i];
$i--;
}
echo $newStr; // output: ayeh
回答by Miguel
Please take a look the below code: Reverse the string
请看下面的代码：反转字符串
$str = 'abcdefg';
$reverseString = '';
for($i=strlen($str);$i<=strlen($str);$i--){
$reverseString .= $str[$i];
if($i==0)
break;
}
echo $reverseString;
The above code output is:
上面的代码输出是：
gfedcba
回答by ABHISHEK GUPTA
//Program for reversing a string
<?php
class str_rev{
public function Revese_Str($string){
$reverse = '';
$i=0;
while(!empty($string[$i])){
$reverse = $string[$i].$reverse;
$i++;
}
return $reverse;
}
}
$object = new str_rev();
echo $object->Revese_Str('Ayush Jain');
回答by Hemant Kumar
There is another method to do this i.e. "Recursion"
还有另一种方法可以做到这一点，即“递归”
<?php
/*
String reverse without using functions and loop conditions
*/
$str = 'Hello World!';
echo rev($str);
function rev($str)
{
$len = strlen($str);
/* Base case for recursion */
if($len == 1 ){
return $str;
}else{
$len--;
/* extract last character and concatenate at end of string
returned from recursive call on remaining string
*/
return substr($str,$len) . rev(substr($str,0,$len));
}
}
回答by Rakesh
<?php
$string = 'ZEESHAN';
$reverse = '';
$i = 0;
while(!empty($string[$i])){
$reverse = $string[$i].$reverse;
$i++;
}
echo $reverse;
?>
Check complete post: https://www.troposal.com/reverse-string-without-function-php/
检查完整的帖子：https: //www.troposal.com/reverse-string-without-function-php/
回答by Kheshav Sewnundun
You can try it with count_charsand array_sum
你可以试试count_chars和array_sum
<?php
$string = "ZEESHAN";
$count=array_sum(count_chars($string));
for($i=$count -1 ;$i>=0;$i--){
echo $string[$i];
}
?>
If you dont want any php string function you can try this way with krsortand array:
如果您不想要任何 php 字符串函数，您可以使用krsortand尝试这种方式array：
<?php
$string = "ZEESHAN";
$arr = array();
$i=0;
while(isset($string[$i])){
$arr[$i] = $string[$i];
$i++;
}
krsort($arr);
$final = implode("",$arr);
var_dump($final);
?>
回答by Narendrasingh Sisodia
You can use whileand forloop like as
您可以像这样使用while和for循环
$string = "ZEESHAN";
$reverse = "";
$j = 0;
while(isset($string[$j])){
$j++;
}
for($i = $j - 1; $i >= 0; $i--){
$reverse .= $string[$i];
}
echo $reverse;
