PHP Exercises: Find the first non-repeated character in a given string

Last update on May 30 2022 11:48:17 (UTC/GMT +8 hours)

PHP: Exercise-42 with Solution

Write a PHP program to find the first non-repeated character in a given string.

Sample Example:

Input: Green
Output: G
Input: abcdea
Output: b

Sample Solution: -

PHP Code:

<?php
 function find_non_repeat($word) {
  $chr = null;
  for ($i = 0; $i <= strlen($word); $i++) {
     if (substr_count($word, substr($word, $i, 1)) == 1) {
        return substr($word, $i, 1);
     }
  }
}

echo find_non_repeat("Green")."\n";
echo find_non_repeat("abcdea")."\n";
?>

Sample Output:

G                                                           
b

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to print out the multiplication table upto 6*6.
Next: Write a PHP program that multiplies corresponding elements of two given lists.

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC