PHP Exercises: Create a new string of the characters at indexes 0,1,4,5,8,9 ... from a given string
PHP Basic Algorithm: Exercise-36 with Solution
Write a PHP program to create a new string of the characters at indexes 0,1,4,5,8,9 ... from a given string.
Sample Solution:
PHP Code :
<?php
function test($s)
{
$result = "";
for ($i = 0; $i < strlen($s); $i=$i+4)
{
$c = $i + 2;
$n = 0;
$z = $c > strlen($s) ? 1 : 2;
$n = $n + $z;
$result = $result.substr($s, $i, $n);
}
return $result;
}
echo (test("Python"))."\n";
echo (test("JavaScript"))."\n";
echo (test("HTML"))."\n";
Sample Output:
Pyon JaScpt HT
Pictorial Presentation:
Flowchart:
PHP Code Editor:
Contribute your code and comments through Disqus.
Previous: Write a PHP program to compare two given strings and return the number of the positions where they contain the same length 2 substring.
Next: Write a PHP program to count the number of two 5's are next to each other in an array of integers. Also count the situation where the second 5 is actually a 6.
What is the difficulty level of this exercise?
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PHP: Tips of the Day
How to Sort Multi-dimensional Array by Value?
Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:
Example:
function sortByOrder($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
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