Php Program to find Palindrome? - php

Question

Three steps to find the palindrome?
use strrev on the given value
Then split using the str_split.
Then use foreach and concate the split value.
Example
$a = "madam";
$b = strrev($a);
$string_reverse = str_split($b);
$palin = '';
foreach($string_reverse as $value){
$palin.= $value;
}
print $palin;
if($a == $palin){
print "<br>Palindrome";
} else {
print "<br>Not Palindrome";
}
Output
madam
Palindrome

Answer 1

try this:
<?php
function check_plaindrome($string) {
//remove all spaces
$string = str_replace(' ', '', $string);
//remove special characters
$string = preg_replace('/[^A-Za-z0-9\-]/', '', $string);
//change case to lower
$string = strtolower($string);
//reverse the string
$reverse = strrev($string);
if ($string == $reverse) {
echo "<p>It is Palindrome</p>";
}
else {
echo "</p>Not Palindrome</p>";
}
}
$string = "A man, a plan, a canal, Panama";
check_plaindrome($string);
########Output#######
<p>It is Palindrome</p>

Answer 2

To check a string whether it is palindrome or not without PHP function.
<?php
$str = 'level';
$strLen = strlen($str)-1;
$revStr = '';
for($i=$strLen; $i>=0; $i--){
$revStr.=$str[$i];
}
if($revStr == $str)
echo 'Palindrome';
else
echo "Not Palindrome";
?>

Answer 3

function checkpala(string $input){
for( $i=0; $i < strlen($input); $i++){ //for each char in the string
if (substr($input,$i,1) != substr($input, strlen($input)-($i+1),1)){ //get the first char and the last char and compare them. Then get the 2nd and the 2nd from the end and compare them. repeate
//if at any point there is no match, stop checking, return false
//echo "$input is not a palindrome";
return false;
}
}
//if the loop completes and every character checked out, return true.
//echo "$input is a palindrome";
return true;
}

Answer 4

There is a simple way who we can write like this to don't make it complicate:
$a = "1681";
$b = strrev($a);
print $b;
if($a == $b){
print "<br>Plaindrome";
} else {
print "<br>Not Plaindrome";
}

Answer 5

You can try this, it reverses the string or value...
function fn_palindrome($palindrome) {
$reversed = '';
$original = $palindrome;
$string = array(); $j = 0;
$converted = (string) $palindrome;
$palindrome = str_split($converted);
$i = count($palindrome) - 1;
while($i >= 0) {
$string[$j] = $palindrome[$i];
$j++; $i--;
}
$reversed = implode('', $string);
if($reversed == $original) {
return TRUE;
} else {
return FALSE;
}
}

Answer 6

function checkPalindrome($string) {
return $string == strrev($string);
}

Answer 7

<?php
$word = "level"; // declare a varibale
echo "String: " . $word . "<br>";
$reverse = strrev($word); // reverse the word
if ($word == $reverse) // compare if the original word is same as the reverse of the same word
echo 'Output: This string is a palindrome';
else
echo 'Output: This is not a palindrome';
?>

Answer 8

Dummy String to be tested
$s = 'abcdefg';
Reverse the string order
$t = strrev($s);
Get the length of the string
$length = mb_strlen($s);
Variable to be used for concating string while traversing using for loop
$new = '';
Loop to traverse string
for ($i = 0; $i < $length; $i++) {
$new = $s[$i].$new;
}
Check string traversed using for loop is equal to string reversed using PHP function
if ($s == $new){
echo "Yes palindrome";
} else {
echo "No palindrome";
}
If output is yes then it is palindrome otherwise it is Not a palindrome string.
*** I have update the answer.

Answer 9

You can try the following code:
function checkPalindrome($string){
$string = strtolower($string);
$reverse = strrev($string);
if($string == $reverse){
return true;
} else {
return false;
}
}

Answer 10

Try this one..
<?php
$strng = 'SMS';
$rvsstr = '';
$i = 0;
while (!empty($strng[$i])) {
$rvsstr = $strng[$i].$rvsstr;
$i++;
}
// echo $rvsstr;
if ($strng === $rvsstr) {
echo "Number is Palindrome";
} else {
echo "Number is not palindrome";
}
?>

Answer 11

Could it be as simple as this?
function isPalindrome(string $word) : bool
{
$word = strtolower($word);
if(strrev($word) === $word){
return true;
} else {
return false;
}
}
echo isPalindrome('Deleveled');

Answer 12

People are already correct here, anyway simply you can try this.
function checkPalindrome($string) {
$string = strtolower($string);
return $string == strrev($string);
}

Answer 13

function isPalindrome($string): bool {
return strtolower($string) === strtolower(strrev($string));
}

Answer 14

Didn't find solution for my 'kąyąk' problem when You have different characters encoding.
Below is originally from php.net comment changed sligtly by me to see on xdebug in phpStorm whats going on.
public function isPalindrome(): bool {
$r = '';
for ($i = mb_strlen($this->string); $i >= 0; $i--) {
$r .= mb_substr($this->string, $i, 1);
}
for ($i = 0 ; $i <= strlen($r); $i++) {
$o = mb_substr($this->string, $i, 1); // original current char
$s = mb_substr($r, $i, 1); // inverted current char
if ($o != $s) {
return false; // if does not match return false
}
}
return true;
}

Answer 15

$a = readline("Enter word: ");
$i=0;
for ($i=0; $i < strlen($a) && substr($a,$i,1) == substr($a,strlen($a)-($i+1),1); $i++);
echo ($i == strlen($a))?"Pallindrome":"Not Pallindrome";
$i < strlen($a) && substr($a,$i,1) == substr($a,strlen($a)-($i+1),1)
This test is the key where the loop tries to keep checking if the characters starting from the left of the string matches with the characters from the right, and it should continue till all characters are checked or till it doesn't find a matching character.

Answer 16

So, first of all, what is palindrome?
Palindrome is a word, phrase, or sequence that reads the same backward as forward.
So, to know wether the string is a palindrome or not, we only need to reverse the original string and then compare it.
Let's say we want to check wether the string Level is a palindrome or not:
$str = 'Level';
This step is for ignoring the case-sensitivity so Level and level will be considered the same.
$str = strtolower($str);
Then we can use the strrev() to reverse the string, then compare it to the original as follow:
echo (strrev($str) === $str) ? 'Palindrome' : 'Not palindrome';
You can also write it with if-else block if you consider it easier to read:
if (strrev($str) === $str) {
echo "Palindrome";
} else {
echo "Not palindrome";
}
Final code:
$str = 'Level';
$str = strtolower($str);
echo (strrev($str) === $str) ? 'Palindrome' : 'Not palindrome';