I have the following multidimensional array called $existing_combinations
Array
(
[0] => Array
(
[1] => 6
[2] => 7
[3] => 9
)
[1] => Array
(
[1] => 1
[2] => 21
[3] => 9
)
[2] => Array
(
[1] => 1
[2] => 7
[3] => 9
)
)
I then generate a new array ($new_combination) which has a combination of the same set of values. Example:
Array
(
[1] => 6
[2] => 21
[3] => 9
)
I then test if $new_combination exists in $existing_combinations with the following in the hope that I will end with a unique combination in $new_combination:
foreach($existing_combinations as $key => $combination){
while($new_combination == $combination){
$new_combination = generateNewCombination();
}
}
The problem is that if $new_combination matches an array that is not at index 0, then when I generate a new combination I am at risk of this matching a $combination that has already been tested against (and will not be tested again).
Sorry if this is a simple one but I'm struggling to think of how I can ensure $new_combination will always end up unique.
Any ideas?
Thanks
You can use in_array in this case, because php compares arrays as value. So, the code can be:
while(in_array($new_combination = generateNewCombination(), $existing_combinations));
print_r($new_combination);
I wrote the below before realizing that in_array can also see if an array exists within an array. So you can simply do this:
if (!in_array($new_combination, $existing_combinations)) {
// It's unique.
}
In the below outdated bit, see the note on using sort, if a different sequence of the same numbers isn't considered unique for your purposes.
[ For Entertainment ]
May not be the most elegant way around, but I would simply do this to keep it simple:
$combo_hashes = [];
// Implode the existing combos into strings.
foreach($existing as $vals) {
$combo_hashes[] = implode(':', $vals);
}
Then, all you need to check with your new combo is:
// Check if the "hash"-string already exists.
if (!in_array( implode(':', $new_combo), $combo_hashes)) {
// ... and we're unique.
}
This presumes that you consider [1,3,2] different from [2,1,3]. If they are equivalent (I don't know what your use case is), you should sort($vals); before you generate the check-strings.
Merge all the second level arrays and run array_unique() to get rid of the duplicate values.
Related
I searched many thread but i can't find this solution
I have this Array
Array
( [0] => [1] => Array ( [0] => 2019-01-11T23:30:00CET [1] => -12.6 ) [2] => [3] => Array ( [0] => 2019-01-11T23:20:00CET [1] => -12.5 ) [4] => [5] => Array ( [0] => 2019-01-11T23:10:00CET [1] => -12.6 ) [10] => [11] => Array ( [0] => 2019-01-11T22:40:00CET [1] => -12.4 )
I found the path to have the maximum or minimum value ( Column [1] ) from this Array but i need to find the relative Parent
(example the minimum -12.6 is in the [1][0] as 2019-01-11T22:20:00CET)
of this two values that are show in the first column ( Column[0] )
Thanks
If you use array_column() to extract the second column of your data, then you can use min() or max() with that array to pick which one you want. This code then extracts the ones that match using a foreach() and if to check if it matches (not exactly sure what you want as output, but this should help)...
$source = [["2019-01-11T23:30:00CET", -12.6],
["2019-01-11T23:20:00CET", -12.5],
["2019-01-11T23:10:00CET", -12.6]
];
$extract = min(array_column($source, 1)); // or use max()
$output = [];
foreach ($source as $key => $element) {
if ( $element[1] == $extract ) {
// Matches, so add to output
$output[$key] = $element[0];
}
}
print_r($output);
will give
Array
(
[0] => 2019-01-11T23:30:00CET
[2] => 2019-01-11T23:10:00CET
)
You could use array_filter() to extract the matching rows, but a foreach() is enough for a straightforward thing like this (IMHO).
If there is a possibility of blank values or strings in the value column, this may confuse the min() as it will consider the values and compare them as strings, to ensure they are all compared as numbers you can add...
$values = array_map("floatval", array_column($source, 1));
$extract = min($values); // or use max()
The array_map("floatval",... goes through the list and converts them all to float values.
Also, here's a generalized algorithm-sketch for "finding the max in some array", expressed as pseudo-code:
"Leave quietly" if the array is empty, or throw an exception.
Otherwise, assume that the first element in the array is the biggest one.
Now, loop through the remaining elements, testing if each one is, in fact, bigger than the "biggest one" that you have so far. If so, select it as the "biggest."
When the loop is finished, return your answer.
Now – this is what a geek would call "an O(n) algorithm," which is to say that its execution-time will be "on the order of" the number of elements in the array. Well, if this is a "one-off" requirement, that's fine. Whereas if what you actually want to do is to get "more than one" max-element, sorting the array (once, then holding on to the sorted result ...) becomes significantly better, because the sort is going to be O(log(n)) ... "on the order of some logarithm of the number of elements," ... and the subsequent cost of "popping off" elements from that sorted array becomes non-existent.
There are other ways to do it, of course – trees and such - but I've already blathered-on too long here.
I have this array from an AJAX request:
array (
[0] => 'lat,long#id_1'
[1] => 'lat,long#id_2'
[2] => 'lat,long#id_3'
)
The problem here is I'm not gonna have always a 'correct-ordered' array like that, so it may look like this one:
array (
[0] => 'lat,long#id_1'
[1] => 'lat,long#id_2'
[2] => 'lat,long#id_3'
[3] => 'lat,long#id_1'
[4] => 'lat,long#id_3'
[5] => 'lat,long#id_2'
)
I need to get the last array value of every id_X (currently only 3 ids):
array (
[3] => 'lat,long#id_1'
[4] => 'lat,long#id_3'
[5] => 'lat,long#id_2'
)
How can I find each last value of that array based on partial string (id_X)?
First do a reverse sort to ensure the latest values are parsed first. Then run them through a loop, matching the partial string to get the ID, adding the data to an array if the ID index doesn't exist yet. Last values will be added to your array, others will be neglected. Something like this:
rsort($ajaxy);
$lasts = [];
foreach($ajaxy as $str) {
$id = substr($str, strrpos($str, '#') + 1);
if (!isset($lasts[$id])) {
$lasts[$id] = $str;
}
}
var_dump($lasts);
If you have a huge array, and you know the amount of IDs you will be getting, you can add in a check to terminate the loop when all required IDs have been added in to avoid redundant processing.
Otherwise, don't bother with the reverse sort, and simply keep overwriting previous values 'til the end, but I find this a cleaner approach. ^_^
Ran into a little snag and wondering if there is a "best practices" way around it.
So I just learned that "A php foreach will execute on the entire array regardless. Test unsetting a value that is next in iteration. It will iterate on the offset, but the value will be null. – Kevin Peno Dec 22 '09 at 21:31" from How do you remove an array element in a foreach loop?
It's the first part of that that is messing with me. I'm iterating through an array with foreach. It's a search function so I'm removing the element I just searched for, so when the loop runs again its minus that element.
I do NOT want to reindex if at all possible, although if I have to I can.
Array
(
[0] => Array
(
[0] => a
[1] => aa
[2] => aaa
)
[1] => Array
(
[0] => b
[1] => bb
[2] => bbb
)
[2] => Array
(
[0] => c
[1] => cc
[2] => ccc
)
[3] => Array
(
[0] => d
[1] => dd
[2] => ddd
)
)
foreach($array as $key=>$value) {
$searchresult[] = search function returns various other keys from array
foreach($searchresult as $deletionid) {
unset($array[$deletionid]);
}
}
So on the first iteration it uses $array[0] obviously but the $searchresults might return 4,5,6,7. So those keys are removed from $array.
Yet the foreach loop still iterates through those and gives me back a bunch of empty arrays.
I did read How does PHP 'foreach' actually work? and I get some of it.
Thanks
In my opinion, the best way to remove array elements based on indexes is to use the array_* set of functions, like array_diff and array_intersect (or array_diff_key and array_intersect_key in your situation).
$indexes_to_remove = array(2,3,4);
$indexes_to_remove = array_flip($indexes_to_remove);
$array = array_diff_key($array,$indexes_to_remove);
If the array is guaranteed to be exhausted at some point, you can use this:
while (true) {
$searchresult[] = search function returns various other keys from array
foreach($searchresult as $deletionid) {
unset($array[$deletionid]);
}
if (count($array) === 0) {
break;
}
}
And yes I know while (true) is pretty evil, but I find in cases like these it does exactly what is needed.
If you want to prevent it from infinite looping you could always add a variable, increment each iteration, and break when it reaches a high value that should never happen (like 10 * count($array))
I have two PHP arrays. One contains a group name and another contains a pay wage value.
$group_wages_array = Array ( [0] => 1 [1] => 4 [2] => 1 [3] => 3 );
This means there are four employees on the schedule. Two are assigned to group 1, another to group 4 and the last to group 3.
The second array is as follows:
$tot_wages_array = Array ( [0] => 500 [1] => 44 [2] => 80 [3] => 11.25 );
This is a sample array of each employee's wage. Both arrays are constructed in order as values are added in a mysql while loop as it pulls the info from the database.
Later on down the line, I combine the two arrays to get one array where the key is the group number and the value is the total wages for that group:
$combined_group_wages = array_combine($group_wages_array, $tot_wages_array);
This works like a charm EXCEPT for when more than one employee is assigned to the same group. These arrays are built in a mysql while loop as it loops through each employee's info:
array_push($tot_wages_array, $totemp_wages_sch); // Add their wage to the array
array_push($group_wages_array, $emp_data['group_id']); // Add their group to the array
Instead of just pushing the data to the array, I need to do this... I know the english but I don't know how to code it:
If $emp_data['group_id'] exists as value in $group_wages_array, add nothing to this array but get the key. Add $totemp_wages_sch to $tot_wages_array where key = group_wages_array key
I know it sounds more like an SQL query but I have to keep the keys and values in order so that they can be combined later in the page. If I can get this to work right, The arrays shown in the example would be:
$group_wages_array = Array ( [0] => 1 [1] => 4 [2] => 3 );
$tot_wages_array = Array ( [0] => 580 [1] => 44 [2] => 11.25 );
$combined_group_wages = array_combine($group_wages_array, $tot_wages_array);
$combined_group_wages = Array ( [1] => 580 [4] => 44 [3] => 11.25 );
...I've got to make this work using PHP. Any ideas?
I came up with a solution based on a combination of two of the answers submitted below. Here it is if it can help someone:
if(in_array($emp_data['group_id'], $group_wages_array)){
$key = key($group_wages_array);
$tot_wages_array[$key] += $totemp_wages_sch;
} else {
array_push($group_wages_array, $emp_data['group_id']);
array_push($tot_wages_array, $totemp_wages_sch);
}
This should do it:
$group_wages_array = array(1, 4, 1, 3);
$tot_wages_array = array(500, 44, 80, 11.25);
$combined_group_wages = array();
for ($i=0; $i<count($group_wages_array); $i++) {
$group = $group_wages_array[$i];
if (array_key_exists($group_wages_array[$group], $combined_group_wages)) {
$combined_group_wages[$group] += $tot_wages_array[$i];
} else {
$combined_group_wages[$group] = $tot_wages_array[$i];
}
}
print_r($combined_group_wages);
Yields:
Array
(
[1] => 580
[4] => 44
[3] => 11.25
)
But I recommend that you just switch to using objects to better represent your data.
If I could see the entirety of the code that would help a lot, but here's your English converted to php. Show me more code and I can perfect it, until then try this ->
if(in_array($emp_data['group_id'], $group_wages_array)){
$key = key($group_wages_array);
$tot_wages_array[$key] = $totemp_wages_sch;
} else {
array_push($group_wages_array, $emp_data['group_id']);
}
I have a page that searches a database and generates the following array. I'd like to be able to loop through the array and pick out the value next assigned to the key "contact_id" and do something with it, but I have no idea how to get down to that level of the array.
The array is dynamically generated, so depending on what I search for the index numbers under "values" will change accordingly.
I'm thinking I have to do a foreach starting under values, but I don't know how to start a foreach at a sublevel of an array.
Array (
[is_error] => 0
[version] => 3
[count] => 2
[values] => Array (
[556053] => Array (
[contact_id] => 556053
[contact_type] => Individual
[first_name] => Brian
[last_name] => YYY
[contact_is_deleted] => 0
)
[596945] => Array (
[contact_id] => 596945
[contact_type] => Individual
[first_name] => Brian
[last_name] => XXX
[contact_is_deleted] => 0
)
)
)
I've looked at the following post, but it seems to only address the situation where the array indices are sequential.
Multidimensional array - how to get specific values from sub-array
Any ideas?
Brian
You are correct in your assumption. You could do something like this:
foreach($array['values'] as $key => $values) {
print $values['contact_id'];
}
That should demonstrate starting at a sub level. I would also add in your checks to see if its empty and if its an array... etc.
Another hint regarding syntax - if the array in your original example is called $a, then the values you want are here:
$a['values'][556053]['contact_id']
and here:
$a['values'][596945]['contact_id']
So if there's no additional structure in your array, then this loop is probably what you want:
foreach ($a['values'] as $toplevel_id => $record_data) {
print "for toplevel_id=[$toplevel_id], contact_id=[" . $record_data['contact_id'] . "]\n";
}
foreach($array['values'] as $sub_arr){
echo $sub_arr['contact_id'];
}