How to select several array elements and check if they are equal to variable

Question

I'm trying to learn PHP on my own just by watching videos and reading blogs. I won't become a pro, I'm just a hobbyist. So I'm trying to code something but I got to a dead end. So I have a string, let's say the string has some numbers f.e. 100, 2000, 3000. Using the explode method I convert the string to an array. Now I have a variable f.e. $var= 50;

I want to see if $var is equal to the first or the third element of the array;

<?php
    $str = " 100, 2000, 3000";
    $fevArr = explode(",", $str);
    $var = 50;
    if ($var == $fevArr['0'] or $var == $fevArr['2'] ) {
        echo "It is";
    } else {
        echo "It is not";
    }
?>

However I might have a lot of numbers in the string and I may want to check if $var is eaqual to many of them (say to the 1th, 10th, 20th, 101th, 300th ect). So I wonder if there is a way to make soemthing like this:

if ($var == $fevArr['0', '9', '19',]) { ....

In other words if there is a way to select several array elements at once.

No, such a syntax does not exist. But you could put the indexes you want to check into another array, and then loop over that, to access each of them in the first array individually. But really you might probably rather want to use something like php.net/manual/en/function.array-search.php — C3roe
– C3roe, Commented Feb 10, 2021 at 8:14

Anurat Chapanond · Accepted Answer · 2021-02-10 08:23:21Z

1

Yes you can use array_keys function. It will return all the indices that match the value you want to look for. Then you can use array_intersect function to check whether those indices match your indices you want to look for.

$var = 50;
$indices = [0, 2];
$keys = array_keys($fevArr, $var);
$matches = array_intersect($indices, $keys);

if(count($matches) > 0) {
   ...
}

answered Feb 10, 2021 at 8:23

Anurat Chapanond

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Comments

mbesson · Accepted Answer · 2021-02-10 08:17:06Z

0

You can use in_array($var, $fevArray) (see documentation) in your if statement.

answered Feb 10, 2021 at 8:17

mbesson

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1 Comment

El_Vanja Over a year ago

Not sure you understood the question right. OP wants to check only specific positions in the array, not the whole array.

Fawkes · Accepted Answer · 2021-02-10 08:22:48Z

0

You can use either array_search (link) which returns the key of the first match and false if no match found OR you can use in_array (link) method which will just check the existance.

answered Feb 10, 2021 at 8:22

Fawkes

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Comments

Shiz · Accepted Answer · 2021-02-10 08:24:39Z

0

in_array() is not consistent just like this

you can use the following code, I got it here

function contains($str, array $arr)
{
    foreach($arr as $a) {
        if (stripos($str,$a) !== false) return true;
    }
    return false;
}

and you can apply it as:

if (contains($var, $fevArr) {
 echo "It is";
}
else {
 echo "It is not";
}

answered Feb 10, 2021 at 8:24

Shiz

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2 Comments

El_Vanja Over a year ago

Not sure you understood the question right. OP wants to check only specific positions in the array, not the whole array.

gogo Over a year ago

It was not what I wanted, but it helped me figure a way around. So thank you!

DrMaxNix · Accepted Answer · 2021-02-14 13:58:34Z

0

<?php
    function contains_at_keys($haystack, $needle, $keys){
        //get all keys matching needle
        $matching_keys = array_keys($haystack, $needle);
        
        //return if these keys contain one or more of the keys to search
        return(sizeof(array_intersect($matching_keys, $keys)) > 0);
    }
    
    
    $str = "100, 2000, 3000, 50, 300, 50, 200";
    $fevArr = explode(",", $str);
    $var = 50;
    
    $keys = [3, 5];
    
    
    if(contains_at_keys($fevArr, $var, $keys)){
        echo("It is");
    } else {
        echo("It is not");
    }
?>

answered Feb 14, 2021 at 13:58

DrMaxNix

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