Passing two variables into a 'foreach' loop - php

I need help regarding a foreach() loop. aCan I pass two variables into one foreach loop?
For example,
foreach($specs as $name, $material as $mat)
{
echo $name;
echo $mat;
}
Here, $specs and $material are nothing but an array in which I am storing some specification and material name and want to print them one by one. I am getting the following error after running:
Parse error: syntax error, unexpected ',', expecting ')' on foreach line.

In the Beginning, was the For Loop:
$n = sizeof($name);
for ($i=0; i < $n; $i++) {
echo $name[$i];
echo $mat[$i];
}

You can not have two arrays in a foreach loop like that, but you can use array_combine to combine an array and later just print it out:
$arraye = array_combine($name, $material);
foreach ($arraye as $k=> $a) {
echo $k. ' '. $a ;
}
Output:
first 112
second 332
But if any of the names don't have material then you must have an empty/null value in it, otherwise there is no way that you can sure which material belongs to which name. So I think you should have an array like:
$name = array('amy','john','morris','rahul');
$material = array('1w','4fr',null,'ff');
Now you can just
if (count($name) == count($material)) {
for ($i=0; $i < $count($name); $i++) {
echo $name[$i];
echo $material[$i];
}
Just FYI: If you want to have multiple arrays in foreach, you can use list:
foreach ($array as list($arr1, $arr2)) {...}
Though first you need to do this: $array = array($specs,$material)
<?php
$abc = array('first','second');
$add = array('112','332');
$array = array($abc,$add);
foreach ($array as list($arr1, $arr2)) {
echo $arr1;
echo $arr2;
}
The output will be:
first
second
112
332
And still I don't think it will serve your exact purpose, because it goes through the first array and then the second array.

You can use the MultipleIterator of SPL. It's a bit verbose for this simple use case, but works well with all edge cases:
$iterator = new MultipleIterator();
$iterator->attachIterator(new ArrayIterator($specs));
$iterator->attachIterator(new ArrayIterator($material));
foreach ($iterator as $current) {
$name = $current[0];
$mat = $current[1];
}
The default settings of the iterator are that it stops as soon as one of the arrays has no more elements and that you can access the current elements with a numeric key, in the order that the iterators have been attached ($current[0] and $current[1]).
Examples for the different settings can be found in the constructor documentation.

This is one of the ways to do this:
foreach ($specs as $k => $name) {
assert(isset($material[$k]));
$mat = $material[$k];
}
If you have ['foo', 'bar'] and [2 => 'mat1', 3 => 'mat2'] then this approach won't work but you can use array_values to discard keys first.
Another apprach would be (which is very close to what you wanted, in fact):
while ((list($name) = each($specs)) && (list($mat) = each($material))) {
}
This will terminate when one of them ends and will work if they are not indexed the same. However, if they are supposed to be indexed the same then perhaps the solution above is better. Hard to say in general.

Do it using a for loop...
Check it below:
<?php
$specs = array('a', 'b', 'c', 'd');
$material = array('x', 'y', 'z');
$count = count($specs) > count($material) ? count($specs) : count($material);
for ($i=0;$i<$count;$i++ )
{
if (isset($specs[$i]))
echo $specs[$i];
if (isset($material[$i]))
echo $material[$i];
}
?>
OUTPUT
axbyczd

Simply use a for loop. And inside that loop, extract values of your array:
For (I=0 to 100) {
Echo array1[i];
Echo array2[i]
}

Related

foreach loop with array?

I have problems with my foreach loop for the $overs array. Here is my code:
$overs[result] = array(0,1,2,3,4,5,6,7);
$overs[market] = array('H6','H7','H8','H9','H10','H11','H12','H13');
foreach ($overs as $row) {
echo $row['result'].'<br/>';
echo $row['market'].'<br/>';
}
I do not get the results like...
0
H6
for the first items for example. All I get is an empty page. No errors. Thanks for your help!
Your $row becomes an array with two arrays. You can't foreach like that.
Use normal for instead:
$overs['result'] = array(0,1,2,3,4,5,6,7);
$overs['market'] = array('H6','H7','H8','H9','H10','H11','H12','H13');
for($i=0; $i<count($overs["result"]);$i++) {
echo $overs['result'][$i]."<br/>\n";
echo $overs['market'][$i]."<br/>\n";
}
https://3v4l.org/kDObN
Not sure what exactly you are looking for but try this out and see if this serves your purpose:
<?php
$a = array(0,1,2,3,4,5,6,7);
$b = array('H6','H7','H8','H9','H10','H11','H12','H13');
$c = array_combine($a, $b);
//print_r($c);
foreach($c as $k => $v){
print $k.'<br>';
print $v.'<br>';
}
?>
Rather than a foreach consider using a for loop
I assume that the arrays in each will be the same size:
<?php
//You were missing the "'" for your keys btw
$overs['result'] = array(0,1,2,3,4,5,6,7);
$overs['market'] = array('H6','H7','H8','H9','H10','H11','H12','H13');
for($i=0; $i < count($overs['result']); $i++){
echo $overs['result'][$i] . '<br>';
echo $overs['market'][$i] . '<br>';
}
Because $row is the two arrays that you would then need to loop over. But to get them one after the other as you show, you would probably need to loop one and access the other by key. Obviously this only works correctly if the arrays are the same length and have the same keys:
foreach ($overs['result'] as $key => $val) {
echo $val.'<br/>';
echo $overs['market'][$key].'<br/>';
}
I assume you mean $overs['result'] and $overs['market'] in your first two lines,
which means it should be:
$overs['result'] = array(0,1,2,3,4,5,6,7);
$overs['market'] = array('H6','H7','H8','H9','H10','H11','H12','H13');
If so, your entire foreach is identical to the following:
echo $overs['result']['result'].'<br/>';
echo $overs['result']['market'].'<br/>';
echo $overs['market']['result'].'<br/>';
echo $overs['market']['market'].'<br/>';
Everything you're echo-ing doesn't exist, which means you should get errors similar to these:
Notice: Undefined index: result in xxx.php on line xxx
Notice: Undefined index: market in xxx.php on line xxx
You should add
error_reporting(E_ALL);
at the beginning of your script.

Finding the first, last and nth row in a foreach loop

I was wondering if PHP has a gracefull method to find the first, last and/or nth row in a foreach loop.
I could do it using a counter as follows:
$i = 0;
$last = count($array)-1;
foreach ($array as $key => $row) {
if ($i == 0) {
// First row
}
if ($i == $last) {
// Last row
}
$i++;
}
But somehow this feels like a bit of a dirty fix. Any solutions or suggestions?
Edit
As suggested in the comments I moved the count($array) outside the loop.
foreach ($array as $key => $row) {
$index = array_search($key, array_keys($array));
if ($index == 0) {
// First row
}
if ($index == count($array) - 1) {
// Last row
}
}
In php we have current and end function to get first and last value of array.
<?php
$transport = array('foot', 'bike', 'car', 'plane');
echo $first = current($transport); // 'foot';
echo $end = end($transport); // 'plane';
?>
Modified :
Easy way without using current or end or foreach loop:
$last = count($transport) - 1;
echo "First : $transport[0]";
echo "</br>";
echo "Last : $transport[$last]";
Using Arrays
For the first element in an array you can simply seek $array[0];. Depending on the array cursor you can also use current($array);
For the middle of an array you can use a combination of array_search() and array_keys().
For the end of an array you can use end($array); noting that this aslso moves the array cursor to the last element as well (as opposed to simply returning the value).
Using Iterators
However ArrayIterator's may also work well in your case:
The first element is available at ArrayIterator::current(); once constructed. (If you're halfway through the iterator you'll need to reset().)
For the n'th or a middle element you can use an undocumented Iterator::seek($index); method.
For the last element you can use a combination of seek() and count().
For example:
$array = array('frank' => 'one',
'susan' => 'two',
'ahmed' => 'three');
$arrayobject = new ArrayObject($array);
$iterator = $arrayobject->getIterator();
// First:
echo $iterator->current() . PHP_EOL;
// n'th: (taken from the documentation)
if($iterator->valid()){
$iterator->seek(1); // expected: two, output: two
echo $iterator->current() . PHP_EOL; // two
}
// last:
$iterator->seek(count($iterator)-1);
echo $iterator->current() . PHP_EOL;
$arr = ["A", "B", "C", "D", "E"];
reset($arr);
// Get First Value From Array
echo current($arr);
// Get Last Value From Array
echo end($arr);
Visit below link for details of above used functions.
reset() : http://php.net/manual/en/function.reset.php
current() : http://php.net/manual/en/function.current.php
end() : http://php.net/manual/en/function.end.php

Reverse order of foreach list items

I would like to reverse the order of this code's list items. Basically it's a set of years going from oldest to recent and I am trying to reverse that output.
<?php
$j=1;
foreach ( $skills_nav as $skill ) {
$a = '<li><a href="#" data-filter=".'.$skill->slug.'">';
$a .= $skill->name;
$a .= '</a></li>';
echo $a;
echo "\n";
$j++;
}
?>
Walking Backwards
If you're looking for a purely PHP solution, you can also simply count backwards through the list, access it front-to-back:
$accounts = Array(
'#jonathansampson',
'#f12devtools',
'#ieanswers'
);
$index = count($accounts);
while($index) {
echo sprintf("<li>%s</li>", $accounts[--$index]);
}
The above sets $index to the total number of elements, and then begins accessing them back-to-front, reducing the index value for the next iteration.
Reversing the Array
You could also leverage the array_reverse function to invert the values of your array, allowing you to access them in reverse order:
$accounts = Array(
'#jonathansampson',
'#f12devtools',
'#ieanswers'
);
foreach ( array_reverse($accounts) as $account ) {
echo sprintf("<li>%s</li>", $account);
}
Or you could use the array_reverse function.
array_reverse() does not alter the source array, but returns a new array. (See array_reverse().) So you either need to store the new array first or just use function within the declaration of your for loop.
<?php
$input = array('a', 'b', 'c');
foreach (array_reverse($input) as $value) {
echo $value."\n";
}
?>
The output will be:
c
b
a
So, to address to OP, the code becomes:
<?php
$j=1;
foreach ( array_reverse($skills_nav) as $skill ) {
$a = '<li><a href="#" data-filter=".'.$skill->slug.'">';
$a .= $skill->name;
$a .= '</a></li>';
echo $a;
echo "\n";
$j++;
}
Lastly, I'm going to guess that the $j was either a counter used in an initial attempt to get a reverse walk of $skills_nav, or a way to count the $skills_nav array. If the former, it should be removed now that you have the correct solution. If the latter, it can be replaced, outside of the loop, with a $j = count($skills_nav).
If you don't mind destroying the array (or a temp copy of it) you can do:
$stack = array("orange", "banana", "apple", "raspberry");
while ($fruit = array_pop($stack)){
echo $fruit . "\n<br>";
}
produces:
raspberry
apple
banana
orange
I think this solution reads cleaner than fiddling with an index and you are less likely to introduce index handling mistakes, but the problem with it is that your code will likely take slightly longer to run if you have to create a temporary copy of the array first.
Fiddling with an index is likely to run faster, and it may also come in handy if you actually need to reference the index, as in:
$stack = array("orange", "banana", "apple", "raspberry");
$index = count($stack) - 1;
while($index > -1){
echo $stack[$index] ." is in position ". $index . "\n<br>";
$index--;
}
But as you can see, you have to be very careful with the index...
You can use usort function to create own sorting rules
Assuming you just need to reverse an indexed array (not associative or multidimensional) a simple for loop would suffice:
$fruits = ['bananas', 'apples', 'pears'];
for($i = count($fruits)-1; $i >= 0; $i--) {
echo $fruits[$i] . '<br>';
}
If your array is populated through an SQL Query consider reversing the result in MySQL, ie :
SELECT * FROM model_input order by creation_date desc
If you do not have Boolean false values in your array, you could use next code based on internal pointer functions:
$array = ['banana', 'apple', 'pineapple', 'lemon'];
$value = end($array);
while ($value !== false) {
// In case you need a key
$key = key($array);
// Do something you need to
echo $key . ' => ' . $value . "\n";
// Move pointer
$value = prev($array);
}
This solution works for associative arrays with arbitrary keys and do not require altering existing or creating a new one.
<?php
$j=1;
array_reverse($skills_nav);
foreach ( $skills_nav as $skill ) {
$a = '<li><a href="#" data-filter=".'.$skill->slug.'">';
$a .= $skill->name;
$a .= '</a></li>';
echo $a;
echo "\n";
$j++;
}
?>

foreach php statement

I need to combine two foreach statement into one for example
foreach ($categories_stack as $category)
foreach ($page_name as $value)
I need to add these into the same foreach statement
Is this possible if so how?
(I am not sure I have understood your question completely. I am assuming that you want to iterate through the two lists in parallel)
You can do it using for loop as follows :
$n = min(count($category), count($value));
for($c = 0; $c < $n; $c = $c + 1){
$categories_stack = $category[$c];
$pagename = $value[$c];
...
}
To achieve the same with foreach you need a function similar to Python's zip() function.
In Python, it would be :
for categories_stack, pagename in zip(categories, values):
print categories_stack, pagename
Since PHP doesn't have a standard zip() function, you'll have to write such a function on your own or go with the for loop solution.
You can do nested foreachs if that's what you want. But without knowing more of your data, it's impossible to say if this helps:
foreach ($categories_stack as $category) {
foreach ($page_name as $value) {
}
}
Probably you want to print out all pages in a category? That probably won't work, so can you give a bit more info on how the arrays look like and relate to each other?
This loop will continue to the length of the longest array and return null for where there are no matching elements in either of the arrays. Try it out!
$a = array(1 => "a",25 => "b", 10 => "c",99=>"d");
$b = array(15=>1,5=>2,6=>3);
$ao = new ArrayObject($a);
$bo = new ArrayObject($b);
$ai = $ao->getIterator();
$bi = $bo->getIterator();
for (
$ai->rewind(),$bi->rewind(),$av = $ai->current(),$bv = $bi->current();
list($av,$bv) =
array(
($ai->valid() ? $ai->current() : null),
($bi->valid() ? $bi->current() : null)
),
($ai->valid() || $bi->valid());
($ai->valid() ? $ai->next() : null),($bi->valid() ? $bi->next() : null))
{
echo "\$av = $av\n";
echo "\$bv = $bv\n";
}
I cannot really tell from the question exactly how you want to traverse the two arrays. For a nested foreach you simply write
foreach ($myArray as $k => $v) {
foreach ($mySecondArray as $kb => $vb {
}
}
However you can do all sorts of things with some creative use of callback functions. In this case an anonymous function returning two items from each array on each iteration. It's then easy to use the iteration value as an array or split it into variables using list() as done below.
This also has the added benefit of working regardless of key structure. I's purely based on the ordering of array elements. Just use the appropriate sorting function if the elements are out of order.
It does not worry about the length of the arrays as there is no error reported, so make sure you keep an eye out for empty values.
$a = array("a","b","c");
$b = array(1,2,3);
foreach (
array_map(
create_function(
'$a,$b', 'return array($a,$b);'
)
,$a,$b
)
as $value
)
{
list($a,$b) = $value;
echo "\$a = $a\n";
echo "\$b = $b\n";
}
Output
$a = a
$b = 1
$a = b
$b = 2
$a = c
$b = 3
Here's another one for you that stops on either of the lists ending. Same as using min(count(a),count(b). Useful if you have arrays of same length. If someone can make it continue to the max(count(a),count(b)) let me know.
$ao = new ArrayObject($a);
$bo = new ArrayObject($b);
$ai = $ao->getIterator();
$bi = $bo->getIterator();
for (
$ai->rewind(),$bi->rewind();
$av = $ai->current(),$bv=$bi->current();
$ai->next(),$bi->next())
{
echo "\$av = $av\n";
echo "\$bv = $bv\n";
}
This is where the venerable for loop comes in handy:
for(
$i = 0,
$n = sizeof($categories_stack),
$m = sizeof($page_name);
$i < $n && $i < $m;
$i++
) {
$category = $categories_stack[$i];
$value = $page_name[$i];
// do stuff here ....
}
Surely you can just merge the arrays before looping?
$data = array_merge($categories_stack, $page_name);
foreach($data AS $item){
...
}
Do the array elements have a direct correspondence with one another, i.e. is there an element in $page_name for each element in $categories_stack? If so, just iterate over the keys and values (assuming they have the same keys):
foreach ($categories_stack as $key => $value)
{
$category = $value;
$page = $page_name[$key];
// ...
}
Could you just nest them with variables outside the scope of the foreach, or prehaps store the content as an array similar to a KVP setup? My answer is vague but I'm not really sure why you're trying to accomplish this.

How to find the foreach index?

Is it possible to find the foreach index?
in a for loop as follows:
for ($i = 0; $i < 10; ++$i) {
echo $i . ' ';
}
$i will give you the index.
Do I have to use the for loop or is there some way to get the index in the foreach loop?
foreach($array as $key=>$value) {
// do stuff
}
$key is the index of each $array element
You can put a hack in your foreach, such as a field incremented on each run-through, which is exactly what the for loop gives you in a numerically-indexed array. Such a field would be a pseudo-index that needs manual management (increments, etc).
A foreach will give you your index in the form of your $key value, so such a hack shouldn't be necessary.
e.g., in a foreach
$index = 0;
foreach($data as $key=>$val) {
// Use $key as an index, or...
// ... manage the index this way..
echo "Index is $index\n";
$index++;
}
It should be noted that you can call key() on any array to find the current key its on. As you can guess current() will return the current value and next() will move the array's pointer to the next element.
Owen has a good answer. If you want just the key, and you are working with an array this might also be useful.
foreach(array_keys($array) as $key) {
// do stuff
}
You can create $i outside the loop and do $i++ at the bottom of the loop.
These two loops are equivalent (bar the safety railings of course):
for ($i=0; $i<count($things); $i++) { ... }
foreach ($things as $i=>$thing) { ... }
eg
for ($i=0; $i<count($things); $i++) {
echo "Thing ".$i." is ".$things[$i];
}
foreach ($things as $i=>$thing) {
echo "Thing ".$i." is ".$thing;
}
I think best option is like same:
foreach ($lists as $key=>$value) {
echo $key+1;
}
it is easy and normally
PHP arrays have internal pointers, so try this:
foreach($array as $key => $value){
$index = current($array);
}
Works okay for me (only very preliminarily tested though).
I use ++$key instead of $key++ to start from 1. Normally it starts from 0.
#foreach ($quiz->questions as $key => $question)
<h2> Question: {{++$key}}</h2>
<p>{{$question->question}}</p>
#endforeach
Output:
Question: 1
......
Question:2
.....
.
.
.
Jonathan is correct. PHP arrays act as a map table mapping keys to values. in some cases you can get an index if your array is defined, such as
$var = array(2,5);
for ($i = 0; $i < count($var); $i++) {
echo $var[$i]."\n";
}
your output will be
2
5
in which case each element in the array has a knowable index, but if you then do something like the following
$var = array_push($var,10);
for ($i = 0; $i < count($var); $i++) {
echo $var[$i]."\n";
}
you get no output. This happens because arrays in PHP are not linear structures like they are in most languages. They are more like hash tables that may or may not have keys for all stored values. Hence foreach doesn't use indexes to crawl over them because they only have an index if the array is defined. If you need to have an index, make sure your arrays are fully defined before crawling over them, and use a for loop.
I solved this way, when I had to use the foreach index and value in the same context:
$array = array('a', 'b', 'c');
foreach ($array as $letter=>$index) {
echo $letter; //Here $letter content is the actual index
echo $array[$letter]; // echoes the array value
}//foreach
I normally do this when working with associative arrays:
foreach ($assoc_array as $key => $value) {
//do something
}
This will work fine with non-associative arrays too. $key will be the index value. If you prefer, you can do this too:
foreach ($array as $indx => $value) {
//do something
}
foreach(array_keys($array) as $key) {
// do stuff
}
I would like to add this, I used this in laravel to just index my table:
With $loop->index
I also preincrement it with ++$loop to start at 1
My Code:
#foreach($resultsPerCountry->first()->studies as $result)
<tr>
<td>{{ ++$loop->index}}</td>
</tr>
#endforeach

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