PHP - Type Handling
You have an array
$data = ['x' => 0, 'y' => null, 'z' => '']. Which keys will isset() return true for?You have an array $data = ['x' => 0, 'y' => null, 'z' => '']. Which keys will isset() return true for?
hard📝 Application Q8 of 15
Step-by-Step Solution
Solution:
Step 1: Check isset() on each key
isset() returns false if value is null or variable not set.Step 2: Evaluate each key
'x' = 0 (set, not null) true, 'y' = null false, 'z' = '' (empty string but set) true.Step 3: Verify isset() on empty string
isset('') returns true because variable is set and not null.Final Answer:
'x' and 'z' -> Option BQuick Check:
isset('') = true, isset(null) = false [OK]
Quick Trick: isset() true for set and not null values [OK]
Common Mistakes:
- Thinking isset() false for empty string
- Confusing null and empty string
- Assuming isset() false for 0
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