I have an ordered laravel collection and i need too put element with id = 20 on top, without sorting other elements. Is it possible to do with sortBy?
You can try to use filter method
// Say $originalCollection is the response from the large request, with data from the database
$modifiedCollection = $originalCollection->filter(fn($item) => $item->id === 20)
->concat($originalCollection->filter(fn($item) => $item->id !== 20));
Or to be more intuitive you can use filter and reject methods
$modifiedCollection = $originalCollection->filter(fn($item) => $item->id === 20)
->concat($originalCollection->reject(fn($item) => $item->id === 20));
The $modifiedCollection will have record with id = 20 at the top and rest of the records will remain in the same order as in $originalCollection
if you want to put a specific item at the top of the array, simply add it separately.
$type = ['20' => 'Select Type'] + $your_sorted_array ;
Example:
$country = ['1' => 'Andorra'] + Countries::orderby('nicename')->pluck('name', 'id')->toArray();
Edit 1:Given new information, the on way you could "manually" do this is by using a combination of unset and unshift AFTER the array is built from the collection.
$key_value = $country[20];
unset($country[20]);
array_unshift($country, $key_value );
if your collection is not very large you can use combination of keyBy, pull and prepend methods
$originalCollection = Model::hereYourBigQuery()->get()->keyBy('id');
/*
now collection will look like this
{
'id1' => objectWithId1,
'id2' => objectWithId2,
...
20 => objectWithId20,
...
}
*/
// pull takes off element by its key
$toMakeFirst = $originalCollection->pull(20);
// prepend adding item into begining of the collection
// note that prepend will reindex collection so its keys will be set by default
$originalCollection->prepend($toMakeFirst);
upd:
if you want to stick with sort there is a way
$collection = Model::yourBigQuery()->get();
$sorted = $collection->sort(function($a, $b){return $a->id == 20 ? -1 : 1;})->values();
as said in docs method sort can take closure as argument and utilizes php uasort under the hood
Related
I have the table products with the following structure.
id | name | promote
Where the column promote is of boolean type.
I want to set the value of the boolean column to 1 with the selected rows and set 0 to non-selected rows. I have the following code in the controller to handle this query.
$yes = Tour::whereIn('id', $request->promote)->get();
$no = Tour::whereNotIn('id', $request->promote)->get();
foreach ($yes as $item) {
$item->promote = 1;
$item->save();
}
foreach ($no as $item) {
$item->promote = 0;
$item->save();
}
I get following from the form request.
The above code does work but it isn't very efficient I assume. I'm looking for optional ways to achieve the result in a more efficient way.
Instead retrieving result, looping through, you can update directly,
$yes = Tour::whereIn('id', $request->promote)->update(['promote' => 1]);
$no = Tour::whereNotIn('id', $request->promote)->update(['promote' => 0]);
If you don't care about going through the Model to do the updating you can call update on the builder to update all the matched records. As this will use the builder and not the Model there will not be any model events fired:
// set them all to promote = 0
Tour::update(['promote' => 0]);
// or just set the ones that need to be 0
Tour::whereNotIn('id', $request->promote)->update(['promote' => 0]);
// set the ones you want to promote = 1
Tour::whereIn('id', $request->promote)->update(['promote' => 1]);
Just one way to give it a go.
I've several collections, I want to keep only the elements that are present in each collection.
I went through the available methods, but I didn't find anything that would match.
$candidatesByConsultant = Consultant::find(request('consultant_id'))->candidates;
$candidatesByCreation = Candidate::whereBetween('created_at',[Carbon::parse(request('meeting_since')), Carbon::parse(request('meeting_to'))])->get();
Do you have any idea? :)
In order to have values that only present in both collection you must use intersect method:
$result = $candidatesByConsultant->intersect($candidatesByCreation);
The intersect method intersects the values of both collections. You can read it in Laravel's official documentation.
And in order to get have results that are not present in both collection you must use diff method:
$result = $candidatesByConsultant->diff($candidatesByCreation);
The diff method finds differences between collections. You can read it in Laravel's official documentation.
The intersect method may be suitable : https://laravel.com/docs/5.8/collections#method-intersect
Example taken from the documentation:
$collection = collect(['Desk', 'Sofa', 'Chair']);
$intersect = $collection->intersect(['Desk', 'Chair', 'Bookcase']);
$intersect->all();
// [0 => 'Desk', 2 => 'Chair']
However, especially if you are trying to intersect multiple collections of Eloquent models, it may not work since the equality between two models is defined by the Model::is() method. Check
https://laravel.com/docs/5.8/eloquent#comparing-models for more information about comparing two Eloquent models.
To handle this, I would do the following, assuming the primary key of your models is id:
$candidatesByConsultant = Consultant::find(request('consultant_id'))->candidates;
$candidatesByCreation = Candidate::whereBetween('created_at',[Carbon::parse(request('meeting_since')), Carbon::parse(request('meeting_to'))])->get();
$candidates = $candidatesByConsultant->merge($candidatesByCreation)->unique("id");
You may check the merge() and unique() documentations.
The built-in for this is $collection->intersect($other), but you can also achieve the desired result with a simple custom filter:
$left = collect([Model::find(1), Model::find(2), Model::find(3)]);
$right = collect([Model::find(1), Model::find(3), Model::find(5)]);
$result = $left->filter(function ($value, $key) use ($right) {
return $right->contains(function ($v, $k) use ($value) {
return $v->id === $value->id;
});
});
This will perform model comparison by id. It is not very performant though. Another approach would be to retrieve two arrays of ids, intersect them and filter the merged sets based on this list:
$left = collect([Model::find(1), Model::find(2), Model::find(3)]);
$right = collect([Model::find(1), Model::find(3), Model::find(5)]);
$merged = $left->merge($right);
$ids = array_intersect($left->pluck('id')->toArray(), $right->pluck('id')->toArray());
$result = $merged->filter(function ($value, $key) use ($ids) {
return in_array($value->id, $ids);
});
I guess I am breaking all the rules by deliberately making a duplicate question...
The other question has an accepted answer. It obviously solved the askers problem, but it did not answer the title question.
Let's start from the beginning - the first() method is implemented approximately like this:
foreach ($collection as $item)
return $item;
It is obviously more robust than taking $collection[0] or using other suggested methods.
There might be no item with index 0 or index 15 even if there are 20 items in the collection. To illustrate the problem, let's take this collection out of the docs:
$collection = collect([
['product_id' => 'prod-100', 'name' => 'desk'],
['product_id' => 'prod-200', 'name' => 'chair'],
]);
$keyed = $collection->keyBy('product_id');
Now, do we have any reliable (and preferably concise) way to access nth item of $keyed?
My own suggestion would be to do:
$nth = $keyed->take($n)->last();
But this will give the wrong item ($keyed->last()) whenever $n > $keyed->count(). How can we get the nth item if it exists and null if it doesn't just like first() behaves?
Edit
To clarify, let's consider this collection:
$col = collect([
2 => 'a',
5 => 'b',
6 => 'c',
7 => 'd']);
First item is $col->first(). How to get the second?
$col->nth(3) should return 'c' (or 'c' if 0-based, but that would be inconsistent with first()). $col[3] wouldn't work, it would just return an error.
$col->nth(7) should return null because there is no seventh item, there are only four of them. $col[7] wouldn't work, it would just return 'd'.
You could rephrase the question as "How to get nth item in the foreach order?" if it's more clear for some.
I guess faster and more memory-efficient way is to use slice() method:
$collection->slice($n, 1);
You can try it using values() function as:
$collection->values()->get($n);
Based on Alexey's answer, you can create a macro in AppServiceProvider (add it inside register method):
use Illuminate\Support\Collection;
Collection::macro('getNth', function ($n) {
return $this->slice($n, 1)->first();
});
and then, you can use this throughout your application:
$collection = ['apple', 'orange'];
$collection->getNth(0) // returns 'apple'
$collection->getNth(1) // returns 'orange'
$collection->getNth(2) // returns null
$collection->getNth(3) // returns null
you may use offsetGet since Collection class implements ArrayAccess
$lines->offsetGet($nth);
Maybe not the best option, but, you can get item from array inside collection
$collection->all()[0]
I have a collection like that:
Collection {#750 ▼
#items: array:18 [▼
18 => User {#691 ▶}
19 => User {#696 ▶}
20 => User {#701 ▶}
]
}
Where 18, 19, 20 should vary
I tried to call with
$collection->get(0);
$collection->get(1);
$collection->get(2);
But obviously, it doesn't work
I found a workaround with shift, that return first element and remove it from the collection,
$el1 = $collection->shift();
$el2 = $collection->shift();
$el3 = $collection->shift();
But in this case, my original collection is destroyed.
Any idea how I should do it?
You can use slice() method:
$collection->slice(0, 3)
The slice method returns a slice of the collection starting at the given index. If you would like to limit the size of the returned slice, pass the desired size as the second argument.
You can use values() as:
$collection = $collection->values();
then you can use it as:
$collection->get(0);
$collection->get(1);
$collection->get(2);
You can either loop over them:
foreach ($collection as $element) {
// use $element
}
Or you can reset the keys to be sequentially indexed:
$collection = $collection->values();
$element1 = $collection->get(0);
$element2 = $collection->get(1);
$element3 = $collection->get(2);
There are many ways you can access thoes values. For example, you can get keys by calling:
$keys = $collection->keys()
Then call by the ordered keys you wanted:
if (isset($keys[0])) $collection->get($keys[0]);
I am trying to create table headers that sort during a back end call in nhibernate. When clicking the header it sends a string indicating what to sort by (ie "Name", "NameDesc") and sending it to the db call.
The db can get quite large so I also have back end filters and pagination built into reduce the size of the retrieved data and therefore the orderby needs to happen before or at the same time as the filters and skip and take to avoid ordering the smaller data. Here is an example of the QueryOver call:
IList<Event> s =
session.QueryOver<Event>(() => #eventAlias)
.Fetch(#event => #event.FiscalYear).Eager
.JoinQueryOver(() => #eventAlias.FiscalYear, () => fyAlias, JoinType.InnerJoin, Restrictions.On(() => fyAlias.Id).IsIn(_years))
.Where(() => !#eventAlias.IsDeleted);
.OrderBy(() => fyAlias.RefCode).Asc
.ThenBy(() => #eventAlias.Name).Asc
.Skip(numberOfRecordsToSkip)
.Take(numberOfRecordsInPage)
.List();
How can I accomplish this?
One way how to achieve this (one of many, because you can also use some fully-typed filter object etc or some query builder) could be like this draft:
Part one and two:
// I. a reference to our query
var query = session.QueryOver<Event>(() => #eventAlias);
// II. join, filter... whatever needed
query
.Fetch(#event => #event.FiscalYear).Eager
var joinQuery = query
.JoinQueryOver(...)
.Where(() => !#eventAlias.IsDeleted)
...
Part three:
// III. Order BY
// Assume we have a list of strings (passed from a UI client)
// here represented by these two values
var sortBy = new List<string> {"Name", "CodeDesc"};
// first, have a reference for the OrderBuilder
IQueryOverOrderBuilder<Event, Event> order = null;
// iterate the list
foreach (var sortProperty in sortBy)
{
// use Desc or Asc?
var useDesc = sortProperty.EndsWith("Desc");
// Clean the property name
var name = useDesc
? sortProperty.Remove(sortProperty.Length - 4, 4)
: sortProperty;
// Build the ORDER
order = order == null
? query.OrderBy(Projections.Property(name))
: query.ThenBy(Projections.Property(name))
;
// use DESC or ASC
query = useDesc ? order.Desc : order.Asc;
}
Finally the results:
// IV. back to query... call the DB and get the result
IList<Event> s = query
.List<Event>();
This draft is ready to do sorting on top of the root query. You can also extend that to be able to add some order statements to joinQuery (e.g. if the string is "FiscalYear.MonthDesc"). The logic would be similar, but built around the joinQuery (see at the part one)