array(
[0]
name => 'joe'
size => 'large'
[1]
name => 'bill'
size => 'small'
)
I think i'm being thick, but to get the attributes of an array element if I know the value of one of the keys, I'm first looping through the elements to find the right one.
foreach($array as $item){
if ($item['name'] == 'joe'){
#operations on $item
}
}
I'm aware that this is probably very poor, but I am fairly new and am looking for a way to access this element directly by value. Or do I need the key?
Thanks,
Brandon
If searching for the exact same array it will work, not it you have other values in it:
<?php
$arr = array(
array('name'=>'joe'),
array('name'=>'bob'));
var_dump(array_search(array('name'=>'bob'),$arr));
//works: int(1)
$arr = array(
array('name'=>'joe','a'=>'b'),
array('name'=>'bob','c'=>'d'));
var_dump(array_search(array('name'=>'bob'),$arr));
//fails: bool(false)
?>
If there are other keys, there is no other way then looping as you already do. If you only need to find them by name, and names are unique, consider using them as keys when you create the array:
<?php
$arr = array(
'joe' => array('name'=>'joe','a'=>'b'),
'bob' => array('name'=>'bob','c'=>'d'));
$arr['joe']['a'] = 'bbb';
?>
Try array_search
$key = array_search('joe', $array);
echo $array[$key];
If you need to do operations on name, and name is unique within your array, this would be better:
array(
'joe'=> 'large',
'bill'=> 'small'
);
With multiple attributes:
array(
'joe'=>array('size'=>'large', 'age'=>32),
'bill'=>array('size'=>'small', 'age'=>43)
);
Though here you might want to consider a more OOP approach.
If you must use a numeric key, look at array_search
You can stick to your for loop. There are not big differences between it and other methods – the array has always to be traversed linearly. That said, you can use these functions to find array pairs with a certain value:
array_search, if you're there's only one element with that value.
array_keys, if there may be more than one.
Related
I have the following array, I'm trying to append the following ("","--") code
Array
(
[0] => Array
(
[Name] => Antarctica
)
)
Current JSON output
[{"Name":"Antarctica"}]
Desired output
{"":"--","Name":"Antarctica"}]
I have tried using the following:
$queue = array("Name", "Antarctica");
array_unshift($queue, "", "==");
But its not returning correct value.
Thank you
You can prepend by adding the original array to an array containing the values you wish to prepend
$queue = array("Name" => "Antarctica");
$prepend = array("" => "--");
$queue = $prepend + $queue;
You should be aware though that for values with the same key, the prepended value will overwrite the original value.
The translation of PHP Array to JSON generates a dictionary unless the array has only numeric keys, contiguous, starting from 0.
So in this case you can try with
$queue = array( 0 => array( "Name" => "Antarctica" ) );
$queue[0][""] = "--";
print json_encode($queue);
If you want to reverse the order of the elements (which is not really needed, since dictionaries are associative and unordered - any code relying on their being ordered in some specific way is potentially broken), you can use a sort function on $queue[0], or you can build a different array:
$newqueue = array(array("" => "--"));
$newqueue[0] += $queue[0];
which is equivalent to
$newqueue = array(array_merge(array("" => "--"), $queue[0]));
This last approach can be useful if you need to merge large arrays. The first approach is probably best if you need to only fine tune an array. But I haven't ran any performance tests.
Try this:
$queue = array(array("Name" => "Antarctica")); // Makes it multidimensional
array_unshift($queue, array("" => "--"));
Edit
Oops, just noticed OP wanted a Prepend, not an Append. His syntax was right, but we was missing the array("" => "--") in his unshift.
You can try this :
$queue = array("Name" => "Antarctica");
$result = array_merge(array("" => "=="), $queue);
var_dump(array_merge(array(""=>"--"), $arr));
I have two arrays, which I can either do the simple approach, which is do a For Each loop on each array, and if one way is the method, accept it, or vice-versa, or is it possible to set values in an array with the same key value?
Like:
<?php
$Array = Array('UniqueValue' => 'Key',
'UniqueValue_2' => 'Key',
'DifferentValue' => 'Key_2'); // and etc...
?>
I could probably try trial and error, but another method would be somehow integrating the arrays and only reading the values I need?
Thanks for your guys' time.
ah, quick edit. I feel like someone's going to bring this up, so I read Nested array, get items with same key and I tried, but it's not working for me. It reads only the first value, and I'm not breaking the loop. If you want to see the code I'm working with, I'll gladly add it.
Actually, I found a better way to word this, so!
I need to iterate through each array value with the same key in a For Each loop.
Like so:
ForEach($Array as $Key){ // or $Key => $Value
If($Key == 'Key'){
Echo $Value;
}
}
<?php
$Array = Array(
0 => Array('Test', 'Testing', 'Tester'),
1 => Array('Test2'));
Print_R($Array[0]); // Array ( [0] => Test [1] => Testing [2] => Tester )
?>
Ah, I forgot about nesting arrays. Sorry about that, haha, but for anyone who would possibly need an answer, here you go.
if i have the following array:
array(
'var1' => 123,
'var2' => 234,
'var3' => 345
);
I would like to extract specific parts of this to build a new array i.e. var1 and var3.
The result i would be looking for is:
array(
'var1' => 123,
'var3' => 345
);
The example posted is very stripped down, in reality the array has a much larger number of keys and I am looking to extract a larger number of key and also some keys may or may not be present.
Is there a built in php function to do this?
Edit:
The keys to be extracted will be hardcoded as an array in the class i..e $this->keysToExtract
$result = array_intersect_key($yourarray,array_flip(array('var1','var3')));
So, with your edit:
$result = array_intersect_key($yourarray,array_flip($this->keysToExtract));
You don't need a built in function to do this, try this :
$this->keysToExtract = array('var1', 'var3'); // The keys you wish to transfer to the new array
// For each record in your initial array
foreach ($firstArray as $key => $value)
{
// If the key (ex : 'var1') is part of the desired keys
if (in_array($key, $this->keysToExtract)
{
$finalArray[$key] = $value; // Add to the new array
}
}
var_dump($finalArray);
Note that this is most likely the most efficient way to do this.
Lets say I have an multidimensional string array:
.food = array(
'vegetable' => array(
'carrot' => 'blablue',
'potato' => 'bluebla',
'cauliflower' => 'blabla'
),
'Fruit' => array(
'apple' => 'chicken65',
'orange' => 'salsafood',
'pear' => 'lokkulakka'
)
);
is it possible to access the array by using index as numbers, instead of using the name of the key?
So for accessing chicken65 , I will type echo $food[1][0]; I don't want to use numbers as key, because its a big array and its more user-friendly if I use string as key and it will let me do for-loops on advanced level.
You can do foreach loops to achieve much the same thing as a typical for-loop.
foreach ($foods as $key => $value) {
//For the first iteration, $key will equal 'vegetable' and $value will be the array
}
$food[1][0] != $food[1]['apple'], so you cannot use numeric keys in this case.
try
$new_array = array_values($food);
however, variable can't start with .. It should start with $
you may want to try the function array_values but since you are dealing with multidemsional arrays, here is a solution posted by a php programmer
http://www.php.net/manual/en/function.array-values.php#103905
but it would be easier to use foreach instead of for.
You can use array_keys() on the array. The resulting array can be traversed via a for-loop and gives you the associative key.
I will show it to you for the first dimension:
$aTest = array('lol' => 'lolval', 'rofl' => 'roflval');
$aKeys = array_keys($aTest);
$iCnt = count($aKeys);
for($i = 0; $i < $iCnt; ++$i)
{
var_dump($aTest[$aKeys[$i]]);
}
You would need to do this for two dimensions but I would not recommend this. It is actually more obstrusive and slower than most other solutions.
I don't think there is something native to go this route.
And it does seem like you are trying to stretch array use a bit.
You should go OOP on this one.
Create a FoodFamilly object and a Food object in which you can store arrays if necessary and you'll be able to write a nice user-friendly code and add indices if needed.
OOP is almost always the answer :)
Which of the following two data structures is "better"?
array('key'=>array(1,2,3,4))
OR:
array('key',array(1,2,3,4))
i.e., is it better to store the array as the second element in a two element array, or as the single element in an array with the key, 'key'.
Assume that for my purposes, in matters of convenience, they are equivalent. I am only curious whether one uses more resources than the other.
You use whichever one is appropriate for what you're trying to store.
If the key relates to the array of values and its unique then use key/value.
Worrying about resources used in this kind of situation are micro-optimizations and an irrelevant distraction.
if that's the full size of the array, then that's fine.
However, if you actually have an array like
array(
array('key', array(...)),
array('key', array(...)),
array('key', array(...)),
etc
);
instead of
array(
'key' => array(...),
'key' => array(...),
'key' => array(...),
);
Then it's not only odd, it's very unreadable.
The beaut thing of having named key to value is this:
"I want the value of Bob"
$bob = $myArray['bob'];
instead of
foreach($myArray as $key => $value) {
if ($value[0] === 'bob') { // the first value of your 2nd type
$bob = $myArray[1]; // get the next value.
}
}
Of course, for the 2nd example you could consider end(). But compare the 2, it is obvious the first example wins!