Get Next Element in Foreach Loop

Get next element in foreach loop

A unique approach would be to reverse the array and then loop. This will work for non-numerically indexed arrays as well:

$items = array(
    'one'   => 'two',
    'two'   => 'two',
    'three' => 'three'
);
$backwards = array_reverse($items);
$last_item = NULL;

foreach ($backwards as $current_item) {
    if ($last_item === $current_item) {
        // they match
    }
    $last_item = $current_item;
}

If you are still interested in using the current and next functions, you could do this:

$items = array('two', 'two', 'three');
$length = count($items);
for($i = 0; $i < $length - 1; ++$i) {
    if (current($items) === next($items)) {
        // they match
    }
}

#2 is probably the best solution. Note, $i < $length - 1; will stop the loop after comparing the last two items in the array. I put this in the loop to be explicit with the example. You should probably just calculate $length = count($items) - 1;

Javascript forEach() through an array: how to get the previous and next item?

Its not working because item is not an array so we cannot write item[index-1].name. Instead, we need to use fruits[index-1] .Also, the first element of the array will not have the previous item and the last element will not have next item.
Code snippet below should work for you.

var fruits = [{
    name: "banana",
    weight: 150
}, {
    name: "apple",
    weight: 130
}, {
    name: "orange",
    weight: 160
}, {
    name: "kiwi",
    weight: 80
}]

fruits.forEach(function(item, index) {
    console.log("Current: " + item.name);
    if (index > 0) {
        console.log("Previous: " + fruits[index - 1].name);
    }
    if (index < fruits.length - 1) {
        console.log("Next: " + fruits[index + 1].name);
    }
});

preview next array element using foreach

The requirement is:

• inside a foreach loop to look at the next value or key but not change the position of the current iterator pointer of the foreach loop.

Although it is more code, one way it to create a completely separate iterator on the same array.

This new iterator has to be kept in step with the foreach loop but that is quite simple to do.

The advantage is that you can manipulate any way you wish using next(), prev(), current() etc. and know that the foreach loop will not be affected.

For this example where the requirement is to test the next entry ahead of th current one. It is worthwhile just starting with the iterator pointing to the second entry and just advance each time.

Example, untested code...

$iter = new \ArrayIterator($cred)s; // mirror of the `foreach` loop 

iterator
foreach($creds as $cred) {

    // get next key and value...
    $iter->next(); 
    $nextKey = $iter->key();
    $nextValue = $iter->current();

    echo $cred['tipo'];

    // if the next item has a 'tipo' key with a specific value
    if($nextValue['tipo']) != '4'){
        echo 'Total';
    }
}

get next element value using foreach loop in php

$wpdb->get_results returns an array of resultset rows and a foreach processes over an array, so the foreach does all the moving down an array, all you need to do is use the $row as the current row you are processing

$results = $wpdb->get_results ( "SELECT * FROM interestclass 
                                where SortingCode='bake1r20210113' || 
                                    SortingCode='bake1r20210225' || 
                                    SortingCode='bake1r20210506' || 
                                    SortingCode='bake1r20210612' || 
                                    SortingCode='bake1r20210813'" );
foreach ( $results as $row )   {   
    echo "<td> working {$row->LessonCode}</td>";
} 

Additional code as per your comment below.

So if you want to test this row against the next row in the array, a simple change to the format of the foreach will provide you with the key to the array. You can then use that on the $results array to gain access to the next occurance in the array. Be careful, its easy doing this to exceed the bounds of the array, so first you need to check that will not happen with a simple IF

$results = $wpdb->get_results ( "SELECT * FROM interestclass 
                                where SortingCode='bake1r20210113' || 
                                    SortingCode='bake1r20210225' || 
                                    SortingCode='bake1r20210506' || 
                                    SortingCode='bake1r20210612' || 
                                    SortingCode='bake1r20210813'" );

$resultCount = count($results);

foreach ( $results as $key => $row ) {   
    // first make sure we have a next row
    if ( $key < $resultCount ){
        $nextRow = $results[$key+1];
        if ( $row->LessonCode == $nextRow->LessonCode ) {
            echo "<td> working {$row->LessonCode}</td>";
        }
    }
} 

how to get next value in array loop?

As it goes below, but remember that your foreach will print only 6 on the last round :)

$test = array(1,2,3,4,5,6);
foreach($test as $index => $value){
   echo $value . $test[$index+1];
}

Don't process next element in forEach loop till the process for first is over

You don't need a recursive function; you need to use the Promise api (async/await), with their buddies .then() .when() .next() etc. The basic problem you are facing is that you need results returned in a certain order, and ajax is asynchronous (things happen when they happen, not necessarily in order) - but you need them in a certain order.

In the beginning was the XMLHttpRequest (XHR), and (for the first time!) it allowed client-side javascript to communicate with a backend server, and receive a response with new data that could be parsed and added to the DOM without leaving or refreshing the page. And it was tricky and difficult, and few there be'd who used it - but it worked.

.then() along came John Resig and he invented jQuery and within it he included the $.ajax() construct, along with its shortcut cousins $.get() $.post() and $.load() - and XHR was significantly easier. And the world rejoiced! But because it was asynchronous, it was still kinda tricky to get the values out of the functions in the right order when you had several related ajax calls to make.

.then() along came the Promise api - because what could be easier than having your code make a Promise and wait for it to be fulfilled? And the world rejoiced once again, and there was no looting. You just set up a promise and .then() you can use .after() and .next() and .when() and, of course, .then() for truly readable code that was as easy to read as it was to write.

And nothing could possibly be easier! Until 2017, when async and await were added to ECMAScript. Now all you have to do is add the keyword async at the top of a function scope, and then within it you can use the await keyword to write those promises for you. Because async/await is really just a wrapper for the Promises api, you can still use .then() .when() .next() etc. - but your code is more readable and simpler to write!

And the world rejoiced, and still there was no looting.

WttW*: This (async/await and Promises api) is something you absolutely must get your head around - it will be more useful to you each day.

^{*Word to the Wise}

References:

https://blog.bitsrc.io/understanding-javascript-async-and-await-with-examples-a010b03926ea

https://petetasker.com/using-async-await-jquerys-ajax/

How do I access the next element in for each loop in Java?

You either need to use an indexed loop.

for(int i=0;i<strings.length-1;i++) {
    String curr = strings[i];
    String next = strings[i+1];
}

or you need to compare the current to the previous not the next.

String curr = null;
for(String next: strings) {
    if (curr != null) {
        // compare
    }
    curr = next;
}

Comparing Next element inside foreach loop in associate array

I don't know where you're getting $date you need 'date', and you're not using $array anywhere in the $c assignment. It can be shortened, but using your code, just check the next element:

foreach($array as $value) {
    $b = $value['date'];
    $c = next($array)['date'] ?? false;
    
    if($b == $c) {     
        echo 'Yes';
    }
}

If they are sequential integer keys then you can do it your way, just check that $key+1 is set:

foreach($array as $key => $value) {
    $b = $value['date'];
    $c = $array[$key+1]['date'] ?? false;
    
    if($b == $c) {     
        echo 'Yes';
    }
}

Get next element of array inside a foreach loop in perl without using next/skipping to next iteration of loop

You can use array indexes:

for my $i (0 .. $#lines) {
    # ...
    print $lines[$i];
    if (cond()) {
        $lines[ $i + 1 ] =~ s/pattern/replace/g;
    }
}

This will, however, process the "next" line again in the next iteration of the loop. If you do not want that, you can use the C-style for:

for (my $i = 0; $i < $#list ; $i++) {
    # ...
}

A more advanced technique would be to define an iterator:

#!/usr/bin/perl
use warnings;
use strict;

sub iterator {
    my $list = shift;
    my $i = 0;
    return sub {
        return if $i > $#$list;
        return $list->[$i++];
    }
}

my @list = qw/a b c d e f g h/;
my $get_next = iterator(\@list);

while (my $member = $get_next->()) {
    print "$member\n";
    if ('d' eq $member) {
        my $next = $get_next->();
        print uc $next, "\n";
    }
}

---

Related Topics