I have an array like this:
$a = array(
array(
'a' => 'x',
'b' => 'asdasd',
),
array(
'a' => 'f',
'b' => '123123qwe',
),
);
And I expect an array like this:
$a = array(
'asdasd',
'123123qwe',
);
I can transform this by iterating and filling a new array,
I wonder if I can do this in 1 line without temporary variables?
Update: Using PHP 5.3 , thanks for the 5.5 suggestions tho!
If you're using PHP 5.5 you can use array_column():
$new_array = array_column($a, 'b');
See it in action
Old school method (pre 5.5):
<?php
function simplify($el)
{
return $el['b'];
}
$a = array(
array(
'a' => 'x',
'b' => 'asdasd',
),
array(
'a' => 'f',
'b' => '123123qwe',
),
);
$a = array_map('simplify',$a);
echo '<pre>'.print_r($a,true).'</pre>';
5.3 method with anonymous function:
$a = array_map(function($el){return $el['b'];},$a);
echo '<pre>'.print_r($a,true).'</pre>';
Related
I have an array that I need to get a value from within the same array that is unassigned to a variable:
return ['a' => 1, 'b'=> 'a', 'c' => 2];
So in this case I need 'b' to return the same value as 'a'. Which would be 1
Thanks for the help.
edit
I intend on running a function on b's value so the value of b is slightly different than a
return ['a' => 1, 'b'=> myFunction('a'), 'c' => 2];
You can try this way.
foreach ($array as $key => $agent) {
$array[$key]['agent_address_1'] = $agent['agent_company_1'] . ', ' .$agent['agent_address_1'];
unset($array[$key]['agent_company_1']);
}
What you want is not clear.
But i am assuming that you are trying to get the 'b' element of an array to be assigned a value similar to the value of 'a' element of that same array
If that is what you need, this will do it.
<?php
$a = array('a' => 1, 'b' => null, 'c' => 2);
$a['b'] = myFunction($a, 'a');
function myFunction($a, $b)
{
return $a[$b];
}
var_dump($a);
You can then return the array, or do what you want with it.
Maybe something like
<?php
function resolve(array $arr) {
foreach($arr as &$v) {
if ( isset($arr[$v])) {
$v = $arr[$v];
}
}
return $arr;
}
function foo() {
return resolve( ['a' => '5', 'b'=>'a', 'c' => '1'] );
}
var_export( foo() );
will do, prints
array (
'a' => '5',
'b' => '5',
'c' => '1',
)
But keep in mind that resolve( ['b'=>'a', 'a' => 'c', 'c' => '1'] ); will return
array (
'b' => 'c',
'a' => '1',
'c' => '1',
)
(you could resolve that with while( isset($arr[$v])) { instead of if ( isset($arr[$v]) ) { ...but there are most likely more elegant/performant ways to do that)
In php is there a way to get an element from each sub array without having to loop - thinking in terms of efficiency.
Say the following array:
$array = array(
array(
'element1' => a,
'element2' => b
),
array(
'element1' => c,
'element2' => d
)
);
I would like all of the 'element1' values from $array
There are a number of different functions that can operate on arrays for you, depending on the output desired...
$array = array(
array(
'element1' => 'a',
'element2' => 'b'
),
array(
'element1' => 'c',
'element2' => 'd'
)
);
// array of element1s : array('a', 'c')
$element1a = array_map(function($item) { return $item['element1']; }, $array);
// string of element1s : 'ac'
$element1s = array_reduce($array, function($value, $item) { return $value . $item['element1']; }, '');
// echo element1s : echo 'ac'
array_walk($array, function($item) {
echo $item['element1'];
});
// alter array : $array becomes array('a', 'c')
array_walk($array, function(&$item) {
$item = $item['element1'];
});
Useful documentation links:
array_map
array_reduce
array_walk
You can use array_map.
Try code below...
$arr = $array = array(
array(
'element1' => a,
'element2' => b
),
array(
'element1' => c,
'element2' => d
)
);
print_r(array_map("getFunc", $arr));
function getFunc($a)
{
return $a['element1'];
}
See Codepad.
But I think array_map will also use loop internally.
If you're running PHP 5.5 (currently the beta-4 is available), then the following
$element1List = array_column($array, 'element1');
should give $element1List as an simple array of just the element1 values for each element in $array
$array = array(
array(
'element1' => a,
'element2' => b
),
array(
'element1' => c,
'element2' => d
)
);
$element1List = array_column($array, 'element1');
print_r($element1List);
gives
Array
(
[0] => a
[1] => c
)
Without loop? Recursion!
$array = array(
array(
'element1' => 'a',
'element2' => 'b'
),
array(
'element1' => 'c',
'element2' => 'd'
)
);
function getKey($array,$key,$new = array()){
$count = count($array);
$new[] = $array[0][$key];
array_shift($array);
if($count==1)
return $new;
return getKey($array,$key,$new);
}
print_R(getKey($array,'element1'));
As I understood from Wikipedia Recursion is not a loop.
How can I split a single array into it's sub-keys?
$arr = array(
0 => array(
'foo' => '1',
'bar' => 'A'
),
1 => array(
'foo' => '2',
'bar' => 'B'
),
2 => array(
'foo' => '3',
'bar' => 'C'
)
);
What is the most efficient way to return an array of foo and bar separately?
I need to get here:
$foo = array('1','2','3');
$bar = array('A','B','C');
I'm hoping there's a clever way to do this using array_map or something similar. Any ideas?
Or do I have to loop through and build each array that way? Something like:
foreach ($arr as $v) {
$foo[] = $v['foo'];
$bar[] = $v['bar'];
}
In a lucky coincidence, I needed to do almost the exact same thing earlier today. You can use array_map() in combination with array_shift():
$foo = array_map('array_shift', &$arr);
$bar = array_map('array_shift', &$arr);
Note that $arr is passed by reference! If you don't do that, then each time it would return the contents of $arr[<index>]['foo']. However, again because of the reference - you won't be able to reuse $arr, so if you need to do that - copy it first.
The downside is that your array keys need to be ordered in the same way as in your example, because array_shift() doesn't actually know what the key is. It will NOT work on the following array:
$arr = array(
0 => array(
'foo' => '1',
'bar' => 'A'
),
1 => array(
'bar' => 'B',
'foo' => '2'
),
2 => array(
'foo' => '3',
'bar' => 'C'
)
);
Update:
After reading the comments, it became evident that my solution triggers E_DEPRECATED warnings for call-time-pass-by-reference. Here's the suggested (and accepted as an answer) alternative by #Baba, which takes advantage of the two needed keys being the first and last elements of the second-dimension arrays:
$foo = array_map('array_shift', $arr);
$bar = array_map('array_pop', $arr);
$n = array();
foreach($arr as $key=>$val) {
foreach($val as $k=>$v) {
$n[$k][] = $v;
}
}
array_merge_recursive will combine scalar values with the same key into an array. e.g.:
array_merge_recursive(array('a',1), array('b',2)) === array(array('a','b'),array(1,2));
You can use this property to simply apply array_merge_recursive over each array in your array as a separate argument:
call_user_func_array('array_merge_recursive', $arr);
You will get this result:
array (
'foo' =>
array (
0 => '1',
1 => '2',
2 => '3',
),
'bar' =>
array (
0 => 'A',
1 => 'B',
2 => 'C',
),
)
It won't even be confused by keys in different order.
However, every merged value must be scalar! Arrays will be merged instead of added as a sub-array:
array_merge_recursive(array(1), array(array(2)) === array(array(1,2))
It does not produce array(array(1, array(2)))!
Is it possible to convert this array:
array(
'A' => 'B',
'C' => 'D',
)
To this array:
array(
array(
'A',
'B',
),
array(
'C',
'D',
),
)
You are probably looking for the array_map (builds pairings based on existing arrays, see Example #4 Creating an array of arrays on the manual page) and the array_keys (all keys of an array) functions:
array_map(null, array_keys($array), $array));
$source = array(
'A' => 'B',
'C' => 'D',
)
foreach ($source as $key => $value){
$result[] = array($key, $value);
}
var_dump($result);
Basically I want some function like array_as_php which is essentially the inverse of eval:
$array = array( '1' => 'b', '2' => 'c' );
echo array_as_php($array);
will print the following eval-able string:
array( '1' => 'b', '2' => 'c' )
var_export() is what you are looking for.
$array = array ('1' => 'b', '2' => 'c' );
echo var_export($array, true);