You want to filter an array in PHP to keep only truthy values (non-empty, non-zero, etc.). Which code correctly uses boolean behavior to achieve this?

hard📝 Application Q15 of 15

PHP - Variables and Data Types

$arr = [0, 1, "", "hello", false, true, null, [], [1]];
$filtered = array_filter($arr, function($v) {
    // What to put here?
});
print_r($filtered);

Areturn $v == true;

Breturn (bool)$v;

Creturn $v === true;

Dreturn !empty($v);

Step-by-Step Solution

Solution:

Step 1: Understand array_filter callback
The callback should return true for values to keep. Casting to (bool) returns true for all truthy values.
Step 2: Compare options
return (bool)$v; casts to boolean correctly. return $v == true; uses loose comparison which may include unwanted values. return $v === true; keeps only true boolean, excluding truthy values. return !empty($v); excludes some truthy values like true boolean but empty arrays are false.
Final Answer:
return (bool)$v; -> Option B
Quick Check:
Cast to bool to filter truthy values [OK]

Quick Trick: Use (bool) cast in filter callback to keep truthy values [OK]

Common Mistakes:

Using strict === true excludes truthy but non-true values
Using == true includes unwanted falsy values
Using empty() excludes some truthy values

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You want to filter an array in PHP to keep only truthy values (non-empty, non-zero, etc.). Which code correctly uses boolean behavior to achieve this?

Step 1: Understand array_filter callback

Step 2: Compare options

Final Answer:

Quick Check:

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