array_map inline anonymous function [duplicate]

Question

I tested inline anonymous function with array_map here

and it worked but when I tried same with $user_meta it is not working.

$user_meta = Array ( [interest] => Array ( [0] => Array ) [type] => 
     Array ( [0] => Array ) [user_status] => Array ( [0] => deny)
     [firstname] => Array ( [0] => ) [lastname] => Array ( [0] => B ) 
     [email] => [email protected] ) 

$user_meta = array_map(function($a) { return $a[0]; },$user_meta);

"Parse error: syntax error, unexpected T_FUNCTION, expecting ')' in"

here is the test link showing error

Socorrosocotra

Your definition of the $user_meta array is not valid for a PHP array, it's print_r() output, formatted for human readability – Tomi

P.S. inline anonymous functions only work in PHP 5.3+ – Jardine

@Paulpro why did you rollback the format change? – Fowlkes

problem in in the email! need to put that in quotes "[email protected]" – Lifeblood

Answer 1

I hope this will help:

$user_meta = array_map(function ($a) { return $a[0]; }, $user_meta);

Caudillo

This is a good answer, except the remark there must be a space between the keyword function and its parameters. Because i removed the space and got no problem. – Bay

The space after function keyword really doesn't matter...! – Koerlin

The space changes nothing. – Lifeblood

Yes, the syntax seems fine. There error should be from $user_meta definition. – Caudillo

Answer 2

There's nothing wrong with the array_map line, but everything before it is wrong. That is the output of a print_r not PHP code. Compare how you define the array in the two links you posted.

Yearlong

I am getting same error when I pass the array with arguments..I could only make it work by calling function explicitly.. here – Socorrosocotra

Which version of PHP do you have? Most people have at least 5.3 now, and you're code worked fine in 5.3 and up. – Yearlong

I am using php 5.5 only you can check the updated link..again it is showing errors – Socorrosocotra

@BLPraveen There are no errors in the section titled: Output for 5.3.0 - 5.5.1. Only in the older version sections. – Yearlong

@BLPraveen Added some output so you can see that's it's working: 3v4l.org/5NgCc – Yearlong

The array syntax is fine... array('0' => '') is just going to define an associative array with a key '0' pointing to an empty string. The error's almost certainly just that he's on a PHP version older than 5.3. – Reasonable

Answer 3

Slightly shorter could be

$user_meta = array_map(fn ($a) => $a[0], $user_meta);

But I would prefer the array_column approach for such an array_map

Blackstone

Answer 4

That's not an answer to your question, but since you want to return the first key of each sub-array, you can just use array_column.

$user_meta = array_column($user_meta, 0);

Bowerbird