Convert foreach to for in PHP - php

foreach ( $this->parent->get_sections(null, $this->parent->author) as $section)
{
//...
}
I'm trying to do is force the loop to output each $section in the order I want. Each $section's name can be retrieved by $section->name. Let's say that I want to output $section "Section 2" first and then "Section 1" (and not in the order of the foreach). How can I force it do that? I presume the proper way would be a for loop with an if checking section names each time.

The proper way would be sorting the results when you call parent->get_sections(). How you would do this is entirely up to the implementation of that class and method. Changing this foreach to for for the sake of sorting seems like a code smell to me.
For the sake of answering the question as technical as possible.
$sections = $this->parent->get_sections(null, $this->parent->author);
$num_sections = count($sections);
for ($i = 0; $i < $num_sections; $i++) {
// what you do here is up to you $sections[$i]
}

Especially if you are not aware of the specific number of sections, you could use usort() to do a dynamic custom sort on the get_sections()-returned array or object and then utilize the existing code. (This is a little more elegant, imo, than doing the same in a for/foreach loop).

Not knowing the structure of your code, I would do something like.
// Get Org Sections
$sections = $this->parent->get_sections(null, $this->parent->author);
// Loop thru sections to get an array of names
foreach ( $sections as $key=>$section)
{
$sorted_sections[$section->name] = $key;
}
// Sort Array
//ksort — Sort an array by key
//krsort — Sort an array by key in reverse order
krsort($sorted_sections);
foreach ( $sorted_sections as $section)
{
// Orig Code
}

$section = $this->parent->get_sections(null, $this->parent->author);
echo $section[2]->name;
echo $section[1]->name;//just output the indexes the way you want
if you want it sorted, in say descending order, you can sort it that way and then use a for loop to display.

Related

MultiDimensionalarray manipulation in php

I have an array like below --
input array
I want the array to be like ----
output
How I can loop through this array to get desired output ?
Kindly guide.
Thanks.
Since you won't put any research effort into the question yourself, I'll just give you the half answer ...
foreach($inputArray as $i) {
$newArray[$i[7]] = $i[8];
}
Now you just have to add them into the specific array. Tip: You need another foreach loop.
Do something like this --
foreach($new_array as $item) //// for looping outer array
{
foreach($item as $n)
{
$newArray[$n[7]] = $n[8]; /// for looping inner array
}
}

Find index of value in associative array in php?

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.

Sorted Array of Objects

Is there any way to maintain a sorted array of objects?
For example, if I have an object with properties ID, Date, Name and a collection of these objects:
$col = array();
public function addNewObject($id, $date, $name)
{
$col[] = new Object($id, $date, $name);
//but instead of appending, it should place it by Name desc
}
If I call something like getObjects, it would return the items in the collection by Name desc.
I think there were some answers for getting objects back in a sorted order, but for efficiency, I would think it be better to sort at insert as the "sort by" variable in my case will never change.
UPDATE:
So based on the comments, I should resort the whole array each time something is added but that seems a bit memory intensive...
Since the array would always be in sorted order to start out with I can identify the location where I want to insert by traversing the array (would this be efficient, is there a better way?). Once I find that how could I "insert" a new object into the array?
I do not imagine that the array will be very large but I would like to implement this the most efficient way possible.
If you're not keen on resorting the array after you add (although I'd recommend it; realistically this wont be a performance issue and it keeps the code readable.
However, if you definitely don't want to do this then you can, as you said, traverse the array and find out where to insert:
$col = array();
public function addNewObject($id, $date, $name){
//Find the index to insert at
$index = 0;
foreach($col as $i => $item){
if($item->name > $name){
//This item is after the item we want to insert.
//Use the previous index and stop traversing
break;
}
$index = $i;
}
$col = array_splice($col, $index, 0, new Object($id, $date, $name));
}
Using array_splice to insert at an arbritary position thanks to https://stackoverflow.com/a/3797526/505722
this is a good example of a function that sorts an array from whatever key you want it sorted by
http://www.php.net/manual/en/function.sort.php#99419
in your example you should run it like :
array_sort($col, 'Name', SORT_DESC));
take in mind that every time you add a new item to the array the whole array is sorted each time

sorting simple_html_dom arrays

I have been trying to get this to work for a while now!
What I am trying to do is sort two arrays, so they both get ordered depending on the values inside one of the arrays. I don't know how to "attach" the arrays so both get ordered.
Here is my code:
$html = file_get_html('http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=hat&x=0&y=0');
$test = strtolower("Beechfield Turn-up Beanie");
$arrayT = array();
$arrayP = array();
foreach ($html->find('div.product') as $results) {
foreach ($results->find('a.title') as $title) {
$titleLow = strtolower($title->plaintext);
similar_text($test, $titleLow, $percent);
$arrayT[] = $title->plaintext;
$arrayP[] = round($percent);
}
}
I am comparing how similar the titles brought back from the outside website are to the variable $test, which in this case is just an example.
Next I want my output to be sorted depending on the $percent variables. For example with no sorting the output would be:
title-1 55
title-2 90
title-3 66
However I want it to be sorted:
title-2 90
title-3 66
title-1 55
I have tried using array_multisort however it would only sort each array independently. I have had a look at usort and ksort as well but couldn't get a working answer.
Any help would be appreciated! I have never used any kind of sorting in PHP and have only started learning arrays so please go easy on me.
I would suggest you to do this:
Instead of storing title and percentage in two different array.
you can have array indices as the titles.
Like this:
$html = file_get_html('http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=hat&x=0&y=0');
$test = strtolower("Beechfield Turn-up Beanie");
$arrayTP = array();
foreach ($html->find('div.product') as $results) {
foreach ($results->find('a.title') as $title) {
$titleLow = strtolower($title->plaintext);
similar_text($one, $titleLow, $percent);
$arrayTP[$title->plaintext] = round($percent);
}
}
You can sort it later using an array sort function based on the percentage. Use this: asort.
Because:
This function sorts an array such that array indices maintain their correlation with the array elements they are associated with. This is used mainly when sorting associative arrays where the actual element order is significant.
For printing do this:
foreach($arrayTP as $title => $percent ) {
.
.
.

Explode the results to add a nested tree to a database in PHP and order it

I'm using a nestedsortable jQuery plugin that gives me the order/sort of the elements serialized.
And example of this serialitzation (root means parent_id=0):
id[1]=root&id[5]=1&id[2]=1&id[3]=1&id[4]=3
First thing I'll do is explode by &:
$serialized = "id[1]=root&id[5]=1&id[2]=1&id[3]=1&id[4]=3";
$exploded = explode("&", $serialized);
But I don't know then how to manage a id[1]=root or id[3]=1. How I can do it?
And another question. In this way I don't know which is how to store the order. When I've the exploded with in array like array("id"=>1, "parent"=>"root"); I've to store the order. I will do it with an index, but how I recognise nested levels?
An example:
$i = 0;
foreach($exploded as $explode)
{
//update every id in MySQL and set parent=$explode["parent"] and order=$i
$i++;
}
But if I've N levels, how I can have a index $i for every one of them?
Thank you in advance!
Rather than exploding, you could try parse_str()
<?php
parse_str("id[1]=root&id[5]=1&id[2]=1&id[3]=1&id[4]=3",$result);
print_r($result);
?>
From there you can work with the array.

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