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PHP PHP Arrays and Control Structures PHP Loops For Looping

question about the use of isset() in the challange

So i figure out the challange but im not 100% sure what's going on:

for ( $i = 1; $i <= 100; $i++ ) {
    echo $i . "\n";
    //if the key exists in the array
    if(isset($facts[$i])) {
        //we show the value of this key
      echo $facts[$i] . "\n";


in the if statment isset is checking if there is an element in the current position of the $i , the $i is lets say in the 57 iteration so

$facts[$i] === $facts["57"]

if there is an element that exists in the current iteration the evulation of the if statement return TRUE if not it return NULL. so in the above example $facts["57"] return true because $i has the same value as one of the existing keys of the $facts array

am i right on how the use of isset() function works here, that's what is happening under the hood?

1 Answer

According to the PHP docs isset returns TRUE if var exists and has any value other than NULL. FALSE otherwise.