PHP: Flattening 1 Dimensional array into a spaced string

Question

After much search (and finding endless posts about multidims, but no single dims) I thought I'd ask this question.

I have an array

$arr = array('foo' => 'bar');

and am looking for an output of

$str = 'foo bar';

This MUST be a one liner, no recursive loops etc etc etc, I am thinking that its going to have to be a lambda of some sort or another. This array will NEVER have more than a single key and a single value though.

I think its going to end up looking something like

$arr = array('foo' => 'bar');
echo 'Authorization: '  . array_walk($arr, function ($v, $k) { echo "$k $v"; });

which unfortunately ends up as foo barAuthorization: 1

no idea where the 1 comes from =P

"no idea where the 1 comes from" : array_walk returns a Boolean value, in your case true which is converted to 1 upon string concatenation. See php.net/manual/en/function.array-walk.php. — Felix Kling
– Felix Kling, Commented Feb 21, 2013 at 1:30
your array_walk is outputting the pairs; you want it to create the string and return it instead. — Mark Reed
– Mark Reed, Commented Feb 21, 2013 at 1:32
Why are you using echo if it needs to go into the CURLOPT_HTTPHEADER parameter? — Barmar
– Barmar, Commented Feb 21, 2013 at 1:42

Mike Brant · Accepted Answer · 2013-02-21 01:46:00Z

7

This should be quite easy since the array was just initialized and the pointer resides at the beginning of the array:

echo 'Authorization: ' . key($arr) . ' ' . current($arr);

Of course if you have already read data from the array you would want to do a reset() before doing this to return the pointer to the beginning of the array.

edited Feb 21, 2013 at 1:46

answered Feb 21, 2013 at 1:36

Mike Brant

71.4k10 gold badges102 silver badges104 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

ehime Over a year ago

Yep works great, waiting to accept =) I forgot that key() existed

AmazingDreams · Accepted Answer · 2013-02-21 01:32:50Z

-1

PHP processes the function before it processes the string in front of it. Try replacing echo in your function with return. I think the 1 comes from the successfull processing of the array_walk function.

echo 'Authorization: '  . array_walk($arr, function ($v, $k) { return "$k $v"; });

UPDATE: Check out Example#1 http://php.net/manual/en/function.key.php

answered Feb 21, 2013 at 1:32

AmazingDreams

3,2342 gold badges24 silver badges32 bronze badges

2 Comments

Felix Kling Over a year ago

The return value of the callback is just ignored. array_walk always returns a Boolean.

AmazingDreams Over a year ago

Then he should iterate over the function with a foreach or something I guess.

Popnoodles · Accepted Answer · 2013-02-21 01:36:30Z

-3

"This array will NEVER have more than a single key and a single value though"

echo 'Authorization: '  .  array_shift(array_keys($arr)). ' ' . array_shift($arr) ;

answered Feb 21, 2013 at 1:36

Popnoodles

28.4k3 gold badges49 silver badges55 bronze badges

Collectives™ on Stack Overflow

PHP: Flattening 1 Dimensional array into a spaced string

3 Answers 3

1 Comment

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest