Convert 'if else' statements to a loop in PHP?

Question

How can I convert this into a loop in PHP?

$number = 4; // This number is unknown and can be any number.

if ($number === 1) {
    echo $red;
} else if ($number === 2) {
    echo $yellow;
} else if ($number === 3) {
    echo $orange;
} else if ($number === 4) {
    echo $black;
} else if ($number === 5) {
    echo $green;
} else if ($number === 6) {
    echo $grey;
} else if ($number === 7) {
    echo $brown;
} else if ($number === 8) {
    echo $blue;
} else if ($number === 9) {
    echo $silver;
} else if ($number === 10) {
    echo $gold;
} else if ($number === 11) {
    echo $white;
} 

etc...

Right now the $number can be any number, so I would have to somehow loop through the numbers from 1 to unlimited, until it finds what $number is equal to. In this case, number is equal to 4.

Answer 1

I'm not sure why you want to do it like this, but:

$i = 1;
while ($i !== $number) {
    $i++;
}
$int = $i;

Answer 2

To do what you want, you should use an array map, but an switch might do the trick too.

PHP don't actually know 1 = one, so you can't iterate through it with a loop. You have to provide this mapping to it, be it by switching instead of loads of ifs, or creating an array map.

Answer 3

Loop is completly the wrong construct for your problem.

Use an array like so:

<?php
$number = 2;
$english = array("zero","one","two","three","four");
echo "file" . $english[$number];
?>

displays filetwo

After OP edit all becomes clear -- try:-

 <?php
    $number = 2;
    $red = "crimson";
    $clear = "glass";
    $yellows = array("gold","lemon","acid","ochre");
    $orange = "tangerine";
    $black = "charcoal";
    $objects = array(&$clear,&$red,&$yellows,&$orange,&$black);

    var_dump( $objects[$number] );

?>

outputs:

array(4) { [0]=> string(4) "gold" [1]=> string(5) "lemon" [2]=> string(4) "acid" [3]=> string(5) "ochre" }

Answer 4

Why not just create a array of items that are the 'lookup table' in the order need like:

$items = ['item_1', 'item_2', 'item_3', … 'item_n'];

or have a string of items like:

$items = explode('|', 'item_1|item_2|item_3|item_n');
//| being the delemiter or what ever might not occur inside any items

then have your $number (might need to minus 1 to $number if items start with 1 and so on to get correct item) used in the array to get the specific item without a loop like:

//$number = 3
$number--;
echo $items[$number];//echos 'item3'

but it almost seems like you then want something like:

//$number = 3
$items = explode('|', 'red|pink|gold|invisible');
echo ${$items[$number - 1]};
//translates into `echo $gold;`
//echos whatever is in $gold

Reading some of your comments it seems like you might be best off to rethink your logic/variables and use arrays and such instead of possibly hundreds of differently named variables that you have to check every time which can't be converted into a simple loop like you wish it could be. The only other possibly is using variables variables like many, including me, have mentioned but you seem to shoot them down. I wouldn't recommend variables variables personally but it would possibly speed up time without needing to do any looping. To effectively minimize code without the need of many if/elses you need to have logic that is consistent.

Answer 5

I think this is what you mean :

echo ${"file" . $number};

But that is showing variable for $filen, for example : $file1, file2, etc. If you want to make it as number, you can do like this :

echo ${"file" . intToEnglish($number)};

You can make intToEnglish(int $number) yourself or need us for help?

I'm not quite sure why you need to loop this, but if you really need to loop this, you can try this :

$i = 0;
while ($i !== $number) {
    $i++;
} 
echo ${"file" . intToEnglish($i)};

But, make sure that echo ${"file" . intToEnglish($number)}; is exist or you will go through infinite looping.

-- EDIT --

This is the case with your edited colour variable case. If you want to make it simple (looping), you muse change how your variable assingned. Example :

$colour = array("green","yellow","red","blue","black");
$i = 0;
while ($i !== $number) {
    $i++;
} 
echo $colour[$i];

Actually that looping is not really necessary until you have process inside it. You can just define it directly like this :

echo $colour[number];

-- EDIT 2 --- This is with checking things :

while($i <= $number) { 
    if($i === $number) { echo $colour[number]; } 
    else { echo 'Checking'. $i; }
}