[Solved] Why does array_flip() lose some keys when flipping an array with duplicate values? — Ans: Because keys in PHP arrays must be unique, duplicates overwrite previous keys | PHP

PHP - Array Functions

Why does array_flip() lose some keys when flipping an array with duplicate values?

ABecause array_flip() only works on numeric keys

BBecause array_flip() converts all values to strings

CBecause array_flip() sorts the array and removes duplicates

DBecause keys in PHP arrays must be unique, duplicates overwrite previous keys

Step-by-Step Solution

Solution:

Step 1: Understand PHP array key uniqueness
PHP arrays require keys to be unique. When flipping, duplicate values become keys, so later keys overwrite earlier ones.
Step 2: Explain why keys are lost
This overwriting causes some original keys to be lost in the flipped array.
Final Answer:
Because keys in PHP arrays must be unique, duplicates overwrite previous keys -> Option D
Quick Check:
array_flip() loses keys due to unique key requirement [OK]

Quick Trick: PHP array keys must be unique; duplicates overwrite in array_flip() [OK]

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Why does array_flip() lose some keys when flipping an array with duplicate values?