Which of the following is the correct syntax to use array_filter with a callback function named isPositive?

easy📝 Syntax Q3 of 15

PHP - Array Functions

Which of the following is the correct syntax to use array_filter with a callback function named isPositive?

A$filtered = array_filter($arr, isPositive());

B$filtered = array_filter('isPositive', $arr);

C$filtered = array_filter($arr, 'isPositive');

D$filtered = array_filter($arr, isPositive);

Step-by-Step Solution

Solution:

Step 1: Recall array_filter syntax
The correct syntax is array_filter(array, callback), where callback is a string with function name.
Step 2: Analyze options
$filtered = array_filter($arr, 'isPositive'); matches the syntax. $filtered = array_filter('isPositive', $arr); reverses parameters. $filtered = array_filter($arr, isPositive()); calls the function instead of passing it. $filtered = array_filter($arr, isPositive); misses quotes around callback.
Final Answer:
$filtered = array_filter($arr, 'isPositive'); -> Option C
Quick Check:
Correct syntax = array_filter(array, 'callback') [OK]

Quick Trick: Pass callback as string without parentheses [OK]

Common Mistakes:

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