The logic required in this case might be simple or not, but I couldn't figure it out. So, I am asking for help.
After a query, I get an array that looks a bit like this:
Array=>
[0]=>
['name'] = item1
['id'] = 1
['parent_id'] = 0
[1]=>
['name'] = item2
['id'] = 2
['parent_id'] = 1
[2]=>
['name'] = item3
['id'] = 3
['parent_id'] = 5
Now, I need to make paths for each and every item in this list. The paths would look something like: /item1 for item1 and something like /item1/item2 for item 2.
Note: The items are not necessarily in order. A parent item might come after it's child...
So, basically, I need a loop (probably more than 1), that when it encounters an item, it writes down the item name preceded by a slash. Then, it looks at the parent_id and writes down the parent_id's name preceded by a slash.
Then it looks at the parent's parent_id and writes down that name preceded by a slash. It continues to do this until it encounters a parent_id of 0. At which point, it assigns a value to an array, so something like paths['item2'] = "/item1/item2" and moves on to the next id and repeats!
Thanks for all your help, have a good day!
edit: Fixed the id of item3, all the items are meant to have different id's.
I was asked to improve the question:
The final output array should look a bit like this:
Array=>
["item1"]="/item1"
["item2"]="/item1/item2"
["item3"]="/item5/item3"
The final output would be a html select form with each item as an option, and I need to have it's path associated somehow, either with a hidden field or just through Ajax or something.
edit: I fixed the problem. I just thought I'd write out the solution here in case someone else stumbles across this.
Note: Still, not exactly sure how it works, but it works! It might be inefficient, I don't know.
function getCollPath($proj_list, $length){
$total_path = "";
$paths = array();
for ($j = 0; $j < $length + 1; $j++){
if (isset($proj_list[$j])){
$id = $j;
$name = $proj_list[$j]['name'];
$total_path = getItemPath($proj_list, $id, NULL);
$paths[$name] = $total_path;
}
}
return $paths;
}
function getItemPath($proj_list, $current_id, $path){
$current_parent_id = $proj_list[$current_id]['parent_id'];
$current_name = $proj_list[$current_id]['name'];
$current_path = "/".$current_name;
if ($current_parent_id == 0){
if (isset($path)){
return $current_path.$path;
}
else{
return $current_path;
}
}
else{
if (!isset($path)){
$path = $current_path;
}
return getItemPath($proj_list, $current_parent_id, $path);
}
}
A recursive function. It looks out for array element with id = child.parent_id. Then it calls self with the current parent_id as parameter until a element with parent_id = "" or "0" is reached. It should return a segment of the breadcrumb to the parent call, so the original call gets the whole route
Related
I have an array that looks like this:
Id = "ADA001"
Stock: 15
The array has about 1700 records that looks the same, how would I search the array for the ID 1 and return the stock?
Edit: I will need to access the stock of each one of these 17000 records
Edit: I have been getting some help from Daniel Centore, he told me to set an arrays primary key to the id of the item and that it is equal to the stock, but I can't get it to work.
I am currently getting the data from an MySQL database and I store it in an array, like so:
$data[] = array();
$getdisposabletest = mysqli_query($connect, "Select id, disposable FROM products");
while ($z = mysqli_fetch_array($getdisposabletest)) {
$data = $z;
}
Now when I use Daniels code that looks like this:
$myMap = [];
foreach($data as $item) {
$myMap[$item['id']] = $item['disposable'];
}
It doesn't return anything when I try to echo my product with the ID "ADA001"
echo $myMap["ADA001"];
Also when I do "count($mymap)" it says its 2 records big, when it should be muuuch larger than that?
Thanks for help
I would use array_filter. Return the result of a comparitor.
$results = array_filter($targetArray, function($el) {
return $el === 1;
});
Edit: Now that it has been made clear that the OP wants to query from thousands of items, the correct way to do this is to make the Id the key to a map in PHP, like this:
$myMap = [];
foreach($array as $item) {
$myMap[$item['Id']] = $item['Stock'];
}
Now, whenever you want to access item '12', simply use $myMap['12'].
The reason this is faster is because of something called algorithmic complexity. You should read about Big-O notation for more info. Essentially, the first operation here is on the order of n and then looping through each of the items that comes out is on the order of n*log(n), so the final result is on the order of n*log(n) which is the best you'll be able to do without more information. However, if you were only accessing one element, just accessing that one element via MySQL would be better because it would be on the order of log(n), which is faster.
Edit 2: Also notice that if you were to access mutliple fields (ie not just the stock) you could do the following:
$myMap = [];
foreach($array as $item) {
$myMap[$item['Id']] = $item;
}
And simply access item 12's stock like this: $myMap['12']['stock'] or its name like this: $myMap['12']['name'].
You would do something like this.
$newArray=[];
foreach($array as $item){
if($item['Id'] === 1){
$newArray[] = $item;
}
}
$stockArray = array_column($newArray,'Stock');
i need to make an array like this
$privateMsgIdArray = array("idlistener" => $idlistener, "maxMsgId" => $lastMsgId);
I need to replace the maxMsgId to the corresponding idlistener, and if the idlistener that i pass doesn't not exist to create a new entry inside the array.
I am a but confused on how i am going to extract the maxMsgId value corresponding to an idlistener.
In other words i need to pass new values of idlisteners only once, and replace maxMsgId each time that they are not equal to the corresponing idlistener.
If the idlistener field doesn't exist create it (push into array).
I pass old array into a session and new array in the current run.
After the run i i replace them.
I believe this sounds a bit confusing though.
e.g
We have an array like this already:
[15][200]
next call maxMsgId is 210
array should be
[15][210]
next call we have a new listener id with maxMsgId 30
array should be
[15][210]
[16][30]
You should be able to accomplish this with a quick loop:
// your "new" values
$idListener = 15;
$maxMsgId = 210;
// loop over the array to see if it contains the `idlistener` you want
$end = count($privateMsgIdArray);
for ($i = 0; $i < $end; $i++) {
if ($privateMsgIdArray[$i]['idlistener'] == $idListener) {
// we found it! overwrite the `maxMsgId` field
$privateMsgIdArray[$i]['maxMsgId'] = $maxMsgId;
break;
}
}
if ($i == $end) {
// we reached the end of the array without finding the `$idListener`;
// add a new entry =]
$privateMsgIdArray[] = array(
'idlistener' => $idListener,
'maxMsgId' => $maxMsgId
);
}
This is a rather brute-force approach though and, if efficiency is something you're after, it would be wise to create a "cache"-style method of idlistener values and their index in the $privateMsgIdArray array.
For instance:
// key = idlistener, value = index in `$privateMsgIdArray`
$idCache = array(15 => 0, 16 => 1);
// check if the `$idListener` is in the cache
if (!isset($idCache[$idListener])) {
// it's not; add a new entry
$key = count($privateMsgIdArray);
$privateMsgIdArray[$key] = array(
'idlistener' => $idListener,
'maxMsgId' => $maxMsgId
);
// add the new index into the cache
$idCache[$idListener] = $key;
} else {
// it is in the cache; pull the corresponding index and set the `maxMsgId` =]
$privateMsgIdArray[$idCache[$idListener]]['maxMsgId'] = $maxMsgId;
}
Both of the approaches above could be converted into functions to make things "more portable" too.
If you have any array $p that you populated in a loop like so:
$p[] = array( "id"=>$id, "Name"=>$name);
What's the fastest way to search for John in the Name key, and if found, return the $p index? Is there a way other than looping through $p?
I have up to 5000 names to find in $p, and $p can also potentially contain 5000 rows. Currently I loop through $p looking for each name, and if found, parse it (and add it to another array), splice the row out of $p, and break 1, ready to start searching for the next of the 5000 names.
I was wondering if there if a faster way to get the index rather than looping through $p eg an isset type way?
Thanks for taking a look guys.
Okay so as I see this problem, you have unique ids, but the names may not be unique.
You could initialize the array as:
array($id=>$name);
And your searches can be like:
array_search($name,$arr);
This will work very well as native method of finding a needle in a haystack will have a better implementation than your own implementation.
e.g.
$id = 2;
$name= 'Sunny';
$arr = array($id=>$name);
echo array_search($name,$arr);
Echoes 2
The major advantage in this method would be code readability.
If you know that you are going to need to perform many of these types of search within the same request then you can create an index array from them. This will loop through the array once per index you need to create.
$piName = array();
foreach ($p as $k=>$v)
{
$piName[$v['Name']] = $k;
}
If you only need to perform one or two searches per page then consider moving the array into an external database, and creating the index there.
$index = 0;
$search_for = 'John';
$result = array_reduce($p, function($r, $v) use (&$index, $search_for) {
if($v['Name'] == $search_for) {
$r[] = $index;
}
++$index;
return $r;
});
$result will contain all the indices of elements in $p where the element with key Name had the value John. (This of course only works for an array that is indexed numerically beginning with 0 and has no “holes” in the index.)
Edit: Possibly even easier to just use array_filter, but that will not return the indices only, but all array element where Name equals John – but indices will be preserved:
$result2 = array_filter($p, function($elem) {
return $elem["Name"] == "John" ? true : false;
});
var_dump($result2);
What suits your needs better, resp. which one is maybe faster, is for you to figure out.
I have a controller function in CodeIgniter that looks like this:
$perm = $this->job_m->getIdByGroup();
foreach($perm as $pe=>$p)
{
$pId = $p['id'];
$result = $this->job_m->getDatapermission($pId);
}
$data['permission'] = $result;
What I need to do is list the data in the result in the view, but I get only the last value while using this method. How can I pass all the results to the view?
Store it in an array. Like this:
foreach($perm as $pe=>$p){
$result[] = $this->job_m->getDatapermission($p['id']);
}
Because $result is not an array...
try this:
$result=array();
foreach($perm as $pe=>$p)
{
$pId = $p['id'];
$result[] = $this->job_m->getDatapermission($pId);
}
$data['permission'] = $result;
Note:
My answer uses a counter to enable the display of a single group result when needed.
Guessing from your need to loop and display the value of $result, possibly, it is an array or object returned by $query->result(). Things could be a bit complex.
Example: if $perm is an array of 5 items( or groups), the counter assigns keys 1 - 5 instead of 0 - 4 as would [] which could be misleading. Using the first view example, you could choose to display a single group value if you wants by passing it via a url segment. Making the code more flexible and reusable. E.g. You want to show just returns for group 2, in my example, $result[2] would do just that else next code runs. See my comments in the code.
$perm = $this->job_m->getIdByGroup();
$counter = 1;
foreach($perm as $pe=>$p)
{
$pId = $p['id'];
$result[$counter] = $this->job_m->getDatapermission($pId);
$counter++;
}
$data['permission'] = $result;
As mentioned above Note:
I Added a Counter or Key so you target specific level. If the groups are:
Men, Women, Boys, Girls, Children; you'd know women is group two(2) If you desire to display values for just that group, you don't need to rewrite the code below. Just pass the group key would be as easy as telling it by their sequence. To display all the loop without restrictions, use the second view example. To use both, use an if statement for that.
###To access it you could target a specific level like
if(isset($permission)){
foreach($permission[2] as $key => $value){
echo $value->columnname;
}
###To get all results:
foreach($permission as $array){
foreach($array as $key => $value){
echo $value->columnname;
}
}
}
I have a large array.
In this array I have got (among many other things) a list of products:
$data['product_name_0'] = '';
$data['product_desc_0'] = '';
$data['product_name_1'] = '';
$data['product_desc_1'] = '';
This array is provided by a third party (so I have no control over this).
It is not known how many products there will be in the array.
What would be a clean way to loop though all the products?
I don't want to use a foreach loop since it will also go through all the other items in the (large) array.
I cannot use a for loop cause I don't know (yet) how many products the array contains.
I can do a while loop:
$i = 0;
while(true) { // doing this feels wrong, although it WILL end at some time (if there are no other products)
if (!array_key_exists('product_name_'.$i, $data)) {
break;
}
// do stuff with the current product
$i++;
}
Is there a cleaner way of doing the above?
Doing a while(true) looks stupid to me or is there nothing wrong with this approach.
Or perhaps there is another approach?
Your method works, as long as the numeric portions are guaranteed to be sequential. If there's gaps, it'll miss anything that comes after the first gap.
You could use something like:
$names = preg_grep('/^product_name_\d+$/', array_keys($data));
which'll return all of the 'name' keys from your array. You'd extract the digit portion from the key name, and then can use that to refer to the 'desc' section as well.
foreach($names as $name_field) {
$id = substr($names, 12);
$name_val = $data["product_name_{$id}"];
$desc_val = $data["product_desc_{$id}"];
}
How about this
$i = 0;
while(array_key_exists('product_name_'.$i, $data)) {
// loop body
$i++;
}
I think you're close. Just put the test in the while condition.
$i = 0;
while(array_key_exists('product_name_'.$i, $data)) {
// do stuff with the current product
$i++;
}
You might also consider:
$i = 0;
while(isset($data['product_name_'.$i])) {
// do stuff with the current product
$i++;
}
isset is slightly faster than array_key_exists but does behave a little different, so may or may not work for you:
What's quicker and better to determine if an array key exists in PHP?
Difference between isset and array_key_exists