indexOf and lastIndexOf in PHP?

Question

In Java, we can use indexOf and lastIndexOf. Since those functions don\'t exist in PHP, what would be the PHP equivalent of this Java code?

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Answer 1

<?php
// sample array
$fruits3 = [
    "iron",
    1,
    "ascorbic",
    "potassium",
    "ascorbic",
    2,
    "2",
    "1",
];

// Let's say we are looking for the item "ascorbic", in the above array

//a PHP function matching indexOf() from JS
echo(array_search("ascorbic", $fruits3, true)); //returns "2"

// a PHP function matching lastIndexOf() from JS world
function lastIndexOf($needle, $arr)
{
    return array_search($needle, array_reverse($arr, true), true);
}

echo(lastIndexOf("ascorbic", $fruits3)); //returns "4"

// so these (above) are the two ways to run a function similar to indexOf and lastIndexOf()

Answer 2

In php:

• stripos() function is used to find the position of the first occurrence of a case-insensitive substring in a string.

• strripos() function is used to find the position of the last occurrence of a case-insensitive substring in a string.

Sample code:

$string = 'This is a string';
$substring ='i';
$firstIndex = stripos($string, $substring);
$lastIndex = strripos($string, $substring);

echo 'Fist index = ' . $firstIndex . ' ' . 'Last index = '. $lastIndex;

Output: Fist index = 2 Last index = 13

Answer 3

You need the following functions to do this in PHP:

strpos Find the position of the first occurrence of a substring in a string

strrpos Find the position of the last occurrence of a substring in a string

substr Return part of a string

Here's the signature of the substr function:

string substr ( string $string , int $start [, int $length ] )

The signature of the substring function (Java) looks a bit different:

string substring( int beginIndex, int endIndex )

substring (Java) expects the end-index as the last parameter, but substr (PHP) expects a length.

It's not hard, to get the desired length by the end-index in PHP:

$sub = substr($str, $start, $end - $start);

Here is the working code

$start = strpos($message, '-') + 1;
if ($req_type === 'RMT') {
    $pt_password = substr($message, $start);
}
else {
    $end = strrpos($message, '-');
    $pt_password = substr($message, $start, $end - $start);
}

Answer 4

This is the best way to do it, very simple.

$msg = "Hello this is a string";
$first_index_of_i = stripos($msg,'i');
$last_index_of_i = strripos($msg, 'i');

echo "First i : " . $first_index_of_i . PHP_EOL ."Last i : " . $last_index_of_i;