I have a 2 dimensions array and need to sort it according to some of the second dimension values.
I tried using uksort, but it doesn't work:
$arr = array();
$arr[] = array('name'=>'test1', 'age'=>25);
$arr[] = array('name'=>'test2', 'age'=>22);
$arr[] = array('name'=>'test3', 'age'=>23);
$arr[] = array('name'=>'test4', 'age'=>29);
uksort($arr, "cmp");
print_r($arr);
function cmp($a, $b) {
if ($a['age']==$b['age']) return 0;
return ($a['age'] < $b['age']) ? -1 : 1;
}
Can anyone spot what am I doing wrong?
I think you are looking for uasort().
uksort() will order your array by keys, but you want to sort the arrays by their value.
uksort
Sort an array by keys using a user-defined comparison function
Sorting array by keys means that you take value of a key (in your case it is the same string age for all subarrays). And you sort by value.
So usort is enough - fiddle.
Related
I have an associative array like this one:
$teams_name_points = array();
$name1 = "name1";
$name2 = "name2";
$teams_name_points[$name1] = 1;
$teams_name_points[$name2] = 2;
I want to sort this array by the key values, currently it's sorted alphabetically by the key.
I tried to implement my own sorting function, but I do not quite understand how it works.
usort($teams_name_points, 'cmp');
function cmp(array $a, array $b){
if ($a['foo'] < $b['foo']) {
return -1;
} else if ($a['foo'] > $b['foo']) {
return 1;
} else {
return 0;
}
}
How do I make the compare method work with my array?
use asort() to sort your array.
http://php.net/manual/en/function.asort.php
This function sorts an array such that array indices maintain their correlation with the array elements they are associated with. This is used mainly when sorting associative arrays where the actual element order is significant.
$teams_name_points = array();
$name1 = "name1";
$name2 = "name2";
$teams_name_points[$name1] = 2;
$teams_name_points[$name2] = 1;
print_r($teams_name_points);
asort($teams_name_points); // sort by value low to high
print_r($teams_name_points);
arsort($teams_name_points); // sort by value high to low
print_r($teams_name_points);
Simply enough, as per the manual, you'll only want to accept the values of the arrays as the arguments to cmp().
E.g.
cmp($earlier_array_value, $later_array_value){
...
}
Also, of course, be aware that usort() is only warranted when you're running a comparison that is custom and not-numerically-straightforward. Simple comparisons by > or < can be more easily done with existing native sort functions.
I have an associative array in which the keys are strings and the values are integers. I'm wanting to first of all sort the array by the values and then sort elements with the same value by their keys. I've managed to sort the array by the values using asort() but haven't worked out how to then sort by the keys.
Any Help?
Thanks
uksort(
$myArray,
function ($a, $b) use ($myArray) {
if ($myArray[$a] == $myArray[$b]) {
return strcmp($a, $b);
}
return ($myArray[$a] < $myArray[$b]) ? -1 : 1;
}
);
I'm reading from a text file that has 2 columns. name,rank So it looks like this:
quxerm,6
brock,5
chris,15
So the 2d array looks like [0][0] = quxerm and [0][1]=6 [1][0] = brock [1][1]=5
I already have them into a 2d array like I showed above.
I need to sort these values in descending order by the integer column. How can I sort this?
#CBergau's answer is almost perfect but the order will be ascending instead of descending.
To get it descending just switch the return values of the compare function which is called by usort. See http://www.php.net/manual/en/function.usort.php for more information.
function cmp(array $a, array $b) {
return ($a[1] < $b[1]) ? 1 : -1;
}
usort($arr, 'cmp');
Example: http://codepad.org/QRTQLxTh
You could also extend the compare function for example to order ascending by name when the rank is the same by using strcmp. See http://www.php.net//manual/en/function.strcmp.php for more information.
function cmp(array $a, array $b) {
if ($a[1] == $b[1]) {
return strcmp($a[0], $b[0]);
}
return ($a[1] < $b[1]) ? 1 : -1;
}
Example: http://codepad.org/SeRTE3Ym
Note: I've not enough reputation yet to just comment on #CBergau's answer.
Use map instead, and then you can use all the functions relatives to maps like this.
take the array as arr[i][j].
try comparing only by changing the values of i.
for(int i=0;i<3;i++)
for(int k=1;k<3;k++)
if(arr[i][1]>arr[k][1])
max=i
and you can retrieve max by :-
arr[max][0]//name of max
arr[max][1]//value of max
$sorted = array();
foreach($yourArray as $a){
$sorted[$a[1]] = $a[0];
}
ksort($sorted);
vardump($sorted);
This should sort by the integer column:
usort(
$data,
function ($arrayOne, $arrayTwo) {
return ($arrayOne[1] < $arrayTwo[1]) ? -1 : 1;
}
);
If there are no duplicate names, you can simply assign the rank for the key (name), and sort that array while preserving keys.
$data["quxerm"] = 6;
$data["brock"] = 5;
$data["chris"] = 15;
asort($data, SORT_NUMERIC);
I have a Multilevel Array (See array structure picture below) and I need to get the sub-nested array with the higher date value.
I was wondering if there is a straight forward way to sort sub-nested arrays by date value or get the highest date value?
Array Map
To do that, usort() function will be useful:
usort($rgData, function($rgX, $rgY)
{
$x = strtotime($rgX['date']);
$y = strtotime($rgY['date']);
return $x<$y?-1:$x!=$y;
});
//var_dump($rgData);
if you want to get highest value, then it will be ['date'] key of last element after doing the sort above.
Edit: if you're sure that format will be exactly same as on picture always, you can use direct string comparison via strcmp (that would be probably faster)
How about using usort():
$input = array(
array('date' => '2013-09-11 13:08:40 +0000'),
array('date' => '2013-09-11 13:09:17 +0000'));
usort($input, function(array $a, array $b) {
$aTimestamp = strtotime($a['date']);
$bTimestamp = strtotime($b['date']);
if($aTimestamp == $bTimestamp) return 0;
return $aTimestamp < $bTimestamp;
});
print_r($input); //$input[0] has the latest date value
I am creating a search capability for a forum program I'm building. At one point I have an array called searchResults which is numeric and contains 'score' as one of its dimensions (others are 'timeStarted', 'authorUID', and 'TID')
So, this array is in disarray at this point and I need to organize it to where $searchResults[1] will be the highest 'score' and [2] will have the second highest, etc. I looked at array_multisort on php.net but got rapidly lost in how it worked. So how would I sort $searchResults in numeric order (rearrange the keys) descending with a descending order of a further dimension 'sort' as the sorting mechanism? There really isn't any code to go with it but if you need a layout of how the array looks, here you go:
$searchResults:
[1] - ['timeStarted']
['authorUID']
['score'] <- Need to sort first dimension by this value descending
['TID']
etc.
Thanks for any help.
usort allows sorting by any specified comparison function
$cmp = function($a,$b) {return $b['score'] - $a['score'];};
usort($searchResults, $cmp);
In this case, $cmp is a function that compares two elements $a and $b of $searchResults based on value of ['score']. $cmp returns 0 for equality, negative val if $a['score'] is greater, positive val if $b['score'] is greater. It would normally be the other way around, but a descending sorting order is desired.
The function you want is usort. Look at example #2:
<?php
function cmp($a, $b)
{
return strcmp($a["fruit"], $b["fruit"]);
}
$fruits[0]["fruit"] = "lemons";
$fruits[1]["fruit"] = "apples";
$fruits[2]["fruit"] = "grapes";
usort($fruits, "cmp");
while (list($key, $value) = each($fruits)) {
echo "\$fruits[$key]: " . $value["fruit"] . "\n";
}
?>
The output:
$fruits[0]: apples
$fruits[1]: grapes
$fruits[2]: lemons