How to find the foreach index

Question

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 an index.

Is there a need to use a for loop, or is there a way to get the index in a foreach ?

Answer 1

 foreach($array as $key=>$value) { // do stuff } 

$key is the index of each element of $array

Answer 2

You can put the hack in your foreach , for example, a field that grows with each pass, which exactly corresponds to the for loop in a numerically indexed array. Such a field will be a pseudo-index, which requires manual control (increments, etc.).

A foreach will give you your index as your $key value, so no such hack is needed.

e.g. in 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++; } 

Answer 3

It should be noted that you can call key() in any array to find the current key. As you can guess, current() will return the current value, and next() move the array pointer to the next element.

Answer 4

Owen has a good answer. If you only need a key and you are working with an array, this can also be useful.

 foreach(array_keys($array) as $key) { // do stuff } 

Answer 5

You can create $i outside the loop and make $i++ at the bottom of the loop.

Answer 6

These two loops are equivalent (e.g. safety railing):

 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; } 

Answer 7

I think the best option is the same:

 foreach ($lists as $key=>$value) { echo $key+1; } 

easy and usual

Answer 8

PHP arrays have internal pointers, so try the following:

 foreach($array as $key => $value){ $index = current($array); } 

Works well for me (only very preliminary tested).

Answer 9

Jonathan is right. PHP arrays act like map maps to values. in some cases, you can get the index if your array is defined, e.g.

 $var = array(2,5); for ($i = 0; $i < count($var); $i++) { echo $var[$i]."\n"; } 

your conclusion will be

 2 5 

and in this case, each element of the array has a knowing 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 have no way out. This is because arrays in PHP are not linear structures, as in most languages. They are more like hash tables, which may or may not have keys for all stored values. Consequently, foreach does not use indexes to traverse 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 going over them and use a for loop.

Answer 10

I usually do this when dealing with associative arrays:

 foreach ($assoc_array as $key => $value) { //do something } 

This will work just fine with non-associative arrays. $ key will be the index value. If you prefer, you can also do this:

 foreach ($array as $indx => $value) { //do something } 

Answer 11

 foreach(array_keys($array) as $key) { // do stuff } 

Answer 12

 foreach($arrvariable as $key=>$value){ echo "$key"; }