Removing an item from an array during a foreach loop - php

I have the following foreach being performed in PHP.
What I would like to do is instead of the $invalid_ids[] = $product_id; building and then looping around that, I would instead like to remove the entry from array that is being looped around as I'm looping around it..
For example:
If the current $product_id fails any of the test, delete the item from the $current_list array and proceed to the next iteration of the foreach loop.
I tried to do an unset($product_id) while the foreach loop header looked like this: foreach ($current_list as &$product_id) {, but the item item is still in the array.
Does anyone have any ideas on how I can go about doing this?
foreach ($current_list as $product_id) {
// Test 1 - Is the product still active?
// How to test? - Search for a product in the (only active) products table
$valid = $db->Execute("SELECT * FROM " . TABLE_PRODUCTS . " WHERE products_id = " . $product_id . " AND products_status = 1");
// Our line to check if this is okay.
if ($valid->RecordCount <= 0) { // We didn't find an active item.
$invalid_ids[] = $product_id;
}
// Test 2 - Is the product sold out?
if ($valid->fields['products_quantity'] <= 0 and STOCK_ALLOW_CHECKOUT == "false") { // We found a sold out item and it is not okay to checkout.
$invalid_ids[] = $product_id;
}
// Test 3 - Does the product have an image?
if (empty($valid->fields['products_image'])) { // Self explanatory.
$invalid_ids[] = $product_id;
}
}

$product_id isn't the actual data in the array, it's a copy of it. You would need to unset the item from $current_list.
I'm don't know how $current_list is stored, but something like unset($current_list['current_item'] would do the trick. You can use key to select the current_item key in the array.
A similar way of iterating the Array, where you can get the array key, from the PHP key docs...
while ($fruit_name = current($array)) {
if ($fruit_name == 'apple') {
echo key($array).'<br />';
}
next($array);
}
Untested, but something like this...
while ($product_id = current($current_list)) {
// Do your checks on $product_id, and if it needs deleting...
$keyToDelete = key($array);
unset($current_list[$keyToDelete]);
next($current_list);
}

I think this simple code may help you
let's say we have an array of integers and we want to remove all the items that are equal to "2" inside of the foreach loop
$array = [1,2,1,2,1,2,1];
foreach ($array as $key => $value)
{
if($value==2)
unset($array[$key]);
}
var_dump($array);
this shows the following result
array (size=4)
0 => int 1
2 => int 1
4 => int 1
6 => int 1

Related

Check if multiple dates are the same in foreach

I have an "Events" table in MySQL :
EventsDate('id','event','start_date','end_date')
I'd like to check if multiple events have the same start date to show it differently in my HTML template.
My SQL request is :
SELECT * FROM EVENTSDATE where event='$id' and start_date>='$today' order by start_date asc
Now my foreach :
foreach ($upcomingDates as $value) { //$upcoming is the array with my sql request
}
How can I say : "if you find two rows with the same start_date, echo something"
I have a slightly different approach.
// Array to contain all values
$container = array();
// Loop through your existing array
foreach ($upcomingDates as $key => $value) {
// Check if the value is already in the container array
// If this is the case, its a duplicate.
if (array_key_exists($value['start_date'], $container)) {
$container[$value['start_date']]++;
echo $value.' is a duplicate with key '.$key;
}
// Add each value to the array
$container[$value['start_date']] = 1;
}
Another method is to use array_count_values()
foreach(array_count_values($upcomingDates) as $value => $c) {
if ($c > 1) {
echo $value.' is a duplicate';
}
}
Note that the second option won't work if your $upcomingDates is an array of arrays.
You can make an empty array before the for loop, and add each value in as a key. Then, on each iteration you can check that array for the key, like so:
$values = [];
foreach ($upcomingDates as $value) { //$upcoming is the array with my sql request
if(isset($values[$value])) //duplicate value found
//do something here
$values[$value] = 1;
}
Since you're ordering your events by start_date:
for ($i = 0, $length = count($upcomingDates); $i < $length; $i++) {
$date = $upcomingDates[$i];
if (isset($upcomingDates[$i + 1]) &&
$upcomingDates[$i + 1]['start_date'] == $date['state_date']) {
echo 'this and the next date are equal';
}
}
Try out GROUP BY
look here: GROUP BY
if you want to find duplicates, then you can directly get it from database
ex.
SELECT * FROM EVENTSDATE where event='$id' and start_date>='$today' GROUP BY start_date having count(start_date) > 1 order by start_date asc
or you can find duplicates from resulting array
return only duplicated entries from an array

Fill Values in multidimensional Array (PHP)

I've got a small problem. I'm working on a little package/product-list.
If you're watching a Package, my website should show you which products are in there.
If a product is more than one time in it, the array should be deleted and the value of the leftover array should be + 1 (each deleted array).
So here's my code:
// $products_in_package has all products in it
// First of all, the products come from a db and don't have a count
// So i first give them a count of 1
foreach ($products_in_package as $product => $value) {
$products_in_package[$product]['count'] = intval(1);
}
foreach ($products_in_package as $product) {
$id_to_find = intval($product['ID']);
$product_count = intval($product['count']);
$found_id = 0;
// Now I try to find any ident products
// If found and over 1 time (beacouse he finds the first too of course)
// Then delete this array and count up the products count
for ($i=0; $i <= count($products_in_package); $i++) {
if(intval($products_in_package[$i]['ID']) === $id_to_find){
$found_id++;
if($found_id > 1){
$product_count = $product_count + 1;
$product['count'] = $product_count;
unset($products_in_package[$i]);
array_merge($products_in_package);
while($i > $products_in_package){
$i = 0;
}
}
}
}
}
What I'm getting is the correct multidimensional array but the count is still 1.
What's wrong with the code?
Everytime I try to log the code i'm getting the right integer. (No, I already tried to delete the chache)
But if I log the array out of the loops, I get always the count of 1.
$product is a copy of the array element, so when you do $product['count'] = $product_count you're assigning to a copy, not the original array.
You can fix this by using a reference in the foreach:
foreach ($products_in_package as &$product) {

How to exclude data from an array?

On a product page I want to show 4 other products selected randomly, but never the product that is already being displayed. The product id of the displayed one is $_product->getId() and all the products go into a $result[] array like this:
foreach($collection as $product){
$result[]=$product->getId();
}
I'm using $need = array_rand($result, 4); to get the ids of the 4 random products, but it might include the id of the product on display. How do I exclude $_product->getId() from the $need[] array? Thank you.
Don't put id of the product you don't want to show into $result:
$currentProductId = $_product->getId();
foreach ($collection as $product) {
if ($product->getId() != $currentProductId) $result[] = $product->getId();
}
Is it acceptable to just not put the current product ID in the array?
foreach($collection as $product) {
if( $product != $_product) $result[] = $product->getId();
}
You might generate your random numbers first, like so:
$rands = array();
while ($monkey == false){
$banana = rand(0,4);
if (in_array($banana, $rands) && $banana != $_product->getId()){ $rands[] = $banana; }
if (sizeOf($rands) == 4){
$monkey = true;
}
}
Then you could pipe them through your product grabber. Obviously, you'd need to figure out the bounds for rand yourself but you know more about your app than I do. Picking your numbers first is much cheaper computationally than pulling records and THEN checking to make sure that they're unique.
Of course, if this is database-backed, you could solve it much more elegantly by writing a new query.
If you use the product id as the index $result[] in result, you can remove the current product from the $result array with unset() before making the call to array_rand() like so:
foreach($collection as $product){
$result[$product->getId()] = $product->getId();
}
unset($result[$_product->getId()]);
$need = array_rand($result, 4);
This approach saves you from having to use the values in $need to look up the product id in your $result[] array, since the values in $need will be your product ids.

Parent Child Relationships PHP/MYSQL

I have a table like this:
id
name
parent_id
I then want to select certain rows based on their id, so something like this:
SELECT *
FROM TABLE
WHERE id IN ('1', '5', '8', '9', '35')
I want to, from this query, also show the parent/child relationship, like:
id parent
-----------
1 0
5 1
8 0
9 8
35 9
So the final output would look something like this:
1
--5
8
--9
----35
Do I do this outside of mysql, i have tried using arrays, but can't figure it out, or
Do I do it inside MYSQL, which i don't know how to do that either.
Here is what I was able to come with which seems to be working great.
PS-Sorry about the formatting, can't figure it out :( (fixed?)
I grab my parent_id and id from MYSQL and put it into an arraly where the array keys are the id's and the values are the parents, so with in the while loop for mysql, something like this: $testarray[$id] = $parent_id;
Then I run it through the functions below, and it orders it just how I need it.
function retrieveSubTree($parent, $myarray) {
$tempArray = $myarray;
$array = array();
//now we have our top level parent, lets put its children into an array, yea!
while ($child = array_search($parent, $tempArray)) {
unset($tempArray[$child]);
//now lets get all this guys children
if (in_array($child, $tempArray)) {
$array[$child] = retrieveSubTree($child, $tempArray);
} else {
$array[$child] = true;
}
}//end while
return (!empty($array)) ? $array : false;
}
function retrieveTree($myarray) {
$array = array();
$counter = 0;
foreach ($myarray as $key => $value) {
$child = $key;
$parent = $value;
//if this child is a parent of somebody else
if (in_array($child, $myarray) && $parent != '0') {
while ($myarray[$parent] != '' && $myarray[$parent] != '0') {
$newparent = $myarray[$parent];
$parent = $newparent;
}
if (!array_key_exists($parent, $array)) {
$array[$parent] = retrieveSubTree($parent, $myarray);
}
} else {
//now make sure they don't appear as some child
if (!array_key_exists($parent, $myarray)) {
//see if it is a parent of anybody
if (in_array($child, $myarray)) {
$array[$child] = retrieveSubTree($child, $myarray);
} else {
$array[$child] = true;
}
}//end if array key
}//end initial in array
}//end foreach
return (!empty($array) ? $array : false);
}
$test = array(
'1'=>'15',
'2'=>'1',
'3'=>'1',
'4'=>'0',
'5'=>'0',
'6'=>'4',
'7'=>'6',
'8'=>'7',
'9'=>'2',
'10'=>'9'
);
print_r(retrieveTree($test));
Without changing your table structure, this requires recursion, which MySQL does not support. You'll have to do it elsewhere. You can write a recursive function in PHP to use, for example, breadth-first search to build your array. Here it looks like you are using parent_id of 0 to denote a top-level object. You can search over your results, and add to your array every object whose parent is zero, which will give you an array with 1 and 8. Then you can recurse: find all the results with a parent of 1, and add that as a subarray to 1; then find all the results with a parent of 8 and add those as a subarray of 8. Continue doing this for each level until you've run out of results.
As other posters pointed out, you can do this natively in MySQL if you can change the table structure.

Simple PHP Array Issue with Key Comparison

I've been pulling my hair out on this one all afternoon. Basically, I have a long table of values (stored in SQL) and I want to go through the entire table and count the number of times each value shows up. I've called the values "pid" integers.
The best way I thought of to do this was to create an array with the PIDs as the key of the array, and the number of times each PID has occured in the table as the value at that key. Then go through the entire list and either add the PID to the array if it didn't already exist, or increment the click value if it already exists. The goal is to then figure out which PID has the highest number of clicks.
It sounds straightforward, and it is! I think I must have an error in my syntax somewhere because everything seems right. This is my first time working with arrays in PHP so be nice :)
Thanks so much!
$tabulation = array();
while ($row = mysql_fetch_array($result)) {
$pid = $row[1];
//if this post isn't in the tabulation array, add it w a click value of 1
if ( !isset( $tabulation[$pid] ) ){ array_push( $tabulation[$pid], 1 ); }
//if this post is already in the tabulation array, incrment its click value by 1
else {
$t = $tabulation[$pid]; $t++; $tabulation[$pid] = $t;
}
}
$highestClicksValue = -1;
$highestClicksPID = -1;
foreach ($tabulation as $pid => $clicks){
if ($clicks > $highestClicksValue){ $highestClicksPID = $pid; }
printf("PID: ". $tabulation[$pid] . " clicks: " . $tabulation[$clicks] . "<br />");
}
I know you're looking for a PHP answer, but have you considered that this is what SQL is best at?
select pid,count(*)
from theTable
group by pid
order by count(*) desc
Just a thought...
Why are you using the array key and value as keys for $tabulation in the last foreach?
This should work...
$tabulation = array();
while ($row = mysql_fetch_array($result)) {
$pid = $row[1];
//if this post isn't in the tabulation array, add it w a click value of 1
if ( ! isset( $tabulation[$pid] ))
$tabulation[$pid] = 1;
//if this post is already in the tabulation array, incrment its click value by 1
else
$tabulation[$pid]++;
}
arsort($tabulation);
$highestClicksValue = reset($tabulation);
$highestClicksPID = key($tabulation);
foreach ($tabulation as $pid => $clicks){
print("PID: ". $pid . " clicks: " . $clicks . "<br />");
}

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