I have the following array
$group= array(
[0] => 'apple',
[1] => 'orange',
[2] => 'gorilla'
);
I run the array group through an for each function and when the loop hits values of gorilla I want it to spit out the index of gorilla
foreach ($group as $key) {
if ($key == gorilla){
echo //<------ the index of gorilla
}
}
You can use array_search function to get the key for specified value:
$key = array_search('gorilla', $group);
foreach( $group as $index => $value) {
if ($value == "gorilla")
{
echo "The index is: $index";
}
}
array_search — Searches the array for a given value and returns the corresponding key if successful
<?php
$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');
$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array); // $key = 1;
?>
foreach($group as $key => $value) {
if ($value=='gorilla') {
echo $key;
}
}
The foreach($c as $k => $v) syntax is similar to the foreach($c as $v) syntax, but it puts the corresponding keys/indices in $k (or whatever variable is placed there) for each value $v in the collection.
However, if you're just looking for the index of a single value, array_search() may be simpler. If you're looking for indices for many values, stick with the foreach.
Try this:
foreach ($group as $key => $value)
{
echo "$key points to $value";
}
foreach documentation on php.net
Related
I need some help with another PHP problem I am working on. I won't be posting the exact question, as I'd prefer to try and apply the knowledge I get from here to solve my problem.
First:
I have an associative array. I must loop through the array to find the array values which have keys that begin with a specific string and push both the key and value to an output array.
eg:
- Loop through the below array & push all elements which have a key beginning with "edible_" to an output array:
$assoc_array = array(
'edible_fruit' => 'apple',
'animal' => 'cat',
'edible_veg' => 'pumpkin',
'number' => '23',
'city' => 'Cape Town',
'edible_berry' => 'blueberry',
'color' => 'blue'
);
Would this work?
$result = array();
foreach ($assoc_array as $key => $value) {
if (substr($key, 0, 7) == "edible_") {
array_push($result, $value);
}
}
print_r($result);
Second:
How would I remove "edible_" from the output array's keys? With this second bit I have no idea where to even begin!
Third:
I've managed to figure out the above with all your help, thank you! Now I just need to find out how I would print each element on a new line with a date & timestamp at the end of each line? I've got this (doesn't seem to be working):
while (list($key, $value) = each($output)) {
print_r("$key => $value" . date("y/m/d G.i:s", time()) . "<br>");
}
First of your code will work.
To remove edible_ from the key you could use explode() -
$keyParts = explode('_', $key);
$newKey = $keyParts[1];
You will have to add the new keys to the array, which you're not doing now.
foreach ($assoc_array as $key => $value) {
if (substr($key, 0, 7) == "edible_") {
$keyParts = explode('_', $key);
$newKey = $keyParts[1];
$result[$newKey] = $value;
}
}
This would be my approach:
foreach($assoc_array as $key => $value) {
if(preg_match("/^edible_/",$key)) {
$result[preg_replace("/^edible_/","",$key)] = $value;
}
}
use preg_match to check if the key starts with what you are looking for and use preg_replace to remove the string from the beginning (^) of the key :)
Input ($assoc_array):
Array
(
[edible_fruit] => apple
[animal] => cat
[edible_veg] => pumpkin
[number] => 23
[city] => Cape Town
[edible_berry] => blueberry
[color] => blue
)
Output ($result):
Array
(
[fruit] => apple
[veg] => pumpkin
[berry] => blueberry
)
First: yes, that would work, however I would rewrite it a bit:
foreach ($assoc_array as $key => $value) {
if (strpos($key, 'edible_') === 0) {
$result[] = $value;
}
}
Regarding Second: You are asking how to remove the key from the output array. However you did not even push the key into the output array, you only pushed the value. If you'd like to also push the key, you should do it like this:
$result[$key] = $value;
But since you haven't done that, there's no need to remove the key.
If you however meant removing the edible_ part of the key from the $assoc_array, you'd just need to add a line to the loop and pass the key by reference by adding a &:
foreach ($assoc_array as &$key => $value) {
if (strpos($key, 'edible_') === 0) {
$key = str_replace('edible_', '', $key)
$result[] = $value;
}
}
Edit: As OP told me in comments, she wants to push the key without the edible part. So just do it like this:
foreach ($assoc_array as $key => $value) {
if (strpos($key, 'edible_') === 0) {
$key = str_replace('edible_', '', $key)
$result[$key] = $value;
}
}
This should work for you:
First I remove all elements, which doesn't have edible_ at the start of the key with array_diff_ukey(). After this I simply array_combine() the elements with they keys, where I remove the prefix with array_map() and substr().
<?php
$assoc_array = array('edible_fruit'=>'apple', 'animal'=>'cat', 'edible_veg'=>'pumpkin', 'number'=>'23', 'city'=>'Cape Town', 'edible_berry'=>'blueberry', 'color'=>'blue');
//remove elemnts
$result = array_diff_ukey($assoc_array, ["edible_" => ""], function($k1, $k2){
return substr($k1, 0, 7) == $k2;
});
//change keys
$result = array_combine(
array_map(function($v){
return substr($v, 7);
}, array_keys($result)),
$result);
print_r($result);
?>
output:
Array ( [fruit] => apple [veg] => pumpkin [berry] => blueberry )
You can loop through the array and search if the key has the string that you can eliminate and make your $newArray
<?php
$assoc_array = array('edible_fruit'=>'apple', 'animal'=>'cat', 'edible_veg'=>'pumpkin', 'number'=>'23', 'city'=>'Cape Town', 'edible_berry'=>'blueberry', 'color'=>'blue');
$search = 'edible_';
$newArray = array();
#First and Second Step
foreach($assoc_array as $key => $value) {
if(strpos($key, "edible_") === 0) {
$newArray[substr($key, 7)] = $value;
}
}
print_r($newArray);
echo "<br>\n";
#Third Step
foreach($newArray as $key => $value) {
echo "$key => $value " . date("y/m/d G.i:s", time()) . "<br>\n";
}
Output:
#First and Second Step
Array ( [fruit] => apple [veg] => pumpkin [berry] => blueberry )
#Third Step
fruit => apple 15/04/10 3.02:16
veg => pumpkin 15/04/10 3.02:16
berry => blueberry 15/04/10 3.02:16
Suppose I have an array like this:
$array = array("a","b","c","d","a","a");
and I want to get all the keys that have the value "a".
I know I can get them using a while loop:
while ($a = current($array)) {
if ($a == 'a') {
echo key($array).',';
}
next($array);
}
How can I get them using a foreach loop instead?
I've tried:
foreach ($array as $a) {
if ($a == 'a') {
echo key($array).',';
}
}
and I got
1,1,1,
as the result.
If you would like all of the keys for a particular value, I would suggest using array_keys, using the optional search_value parameter.
$input = array("Foo" => "X", "Bar" => "X", "Fizz" => "O");
$result = array_keys( $input, "X" );
Where $result becomes
Array (
[0] => Foo
[1] => Bar
)
If you wish to use a foreach, you can iterate through each key/value set, adding the key to a new array collection when its value matches your search:
$array = array("a","b","c","d","a","a");
$keys = array();
foreach ( $array as $key => $value )
$value === "a" && array_push( $keys, $key );
Where $keys becomes
Array (
[0] => 0
[1] => 4
[2] => 5
)
You can use the below to print out keys with specific value
foreach ($array as $key=>$val) {
if ($val == 'a') {
echo $key." ";
}
}
here's a simpler filter.
$query = "a";
$result = array_keys(array_filter($array,
function($element)use($query){
if($element==$query) return true;
}
));
use
foreach($array as $key=>$val)
{
//access the $key as key.
}
Consider the following array:
$array[23] = array(
[0] => 'FOO'
[1] => 'BAR'
[2] => 'BAZ'
);
Whenever I want to work with the inner array, I do something like this:
foreach ($array as $key => $values) {
foreach ($values as $value) {
echo $value;
}
}
The outer foreach-loop is there to split the $key and $value-pairs of $array. This works fine for arrays with many keys ([23], [24], ...)but seems redundant if you know beforehand that $array only has one key (23 in this case). In a case as such, isn't there a better way to split the key from the values? Something like
split($array into $key => $values)
foreach ($values as $value) {
echo $value;
}
I hope I made myself clear.
reset returns the first element of you array and key returns its key:
$your_inner_arr = reset($array);
$your_key = key($array);
Yea, just get rid of your first foreach and define the array you're using with the known $key of your outter array.
foreach ($array[23] as $key =>$val):
//do whatever you want in here
endforeach;
If an array has only one element, you can get it with reset:
$ar = array(23 => array('foo', 'bar'));
$firstElement = reset($ar);
A very succinct approach would be
foreach(array_shift($array) as $item) {
echo $item;
}
I am sure that this is super easy and built-in function in PHP, but I have yet not seen it.
Here's what I am doing for the moment:
foreach($array as $key => $value) {
echo $key; // Would output "subkey" in the example array
print_r($value);
}
Could I do something like the following instead and thereby save myself from writing "$key => $value" in every foreach loop? (psuedocode)
foreach($array as $subarray) {
echo arrayKey($subarray); // Will output the same as "echo $key" in the former example ("subkey"
print_r($value);
}
Thanks!
The array:
Array
(
[subKey] => Array
(
[value] => myvalue
)
)
You can use key():
<?php
$array = array(
"one" => 1,
"two" => 2,
"three" => 3,
"four" => 4
);
while($element = current($array)) {
echo key($array)."\n";
next($array);
}
?>
Use the array_search function.
Example from php.net
$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');
$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array); // $key = 1;
$foo = array('a' => 'apple', 'b' => 'ball', 'c' => 'coke');
foreach($foo as $key => $item) {
echo $item.' is begin with ('.$key.')';
}
$array = array(0 => 100, "color" => "red");
print_r(array_keys($array));
If it IS a foreach loop as you have described in the question, using $key => $value is fast and efficient.
If you want to be in a foreach loop, then foreach($array as $key => $value) is definitely the recommended approach. Take advantage of simple syntax when a language offers it.
Another way to use key($array) in a foreach loop is by using next($array) at the end of the loop, just make sure each iteration calls the next() function (in case you have complex branching inside the loop)
Try this
foreach(array_keys($array) as $nmkey)
{
echo $nmkey;
}
Here is a generic solution that you can add to your Array library. All you need to do is supply the associated value and the target array!
PHP Manual: array_search() (similiar to .indexOf() in other languages)
public function getKey(string $value, array $target)
{
$key = array_search($value, $target);
if ($key === null) {
throw new InvalidArgumentException("Invalid arguments provided. Check inputs. Must be a (1) a string and (2) an array.");
}
if ($key === false) {
throw new DomainException("The search value does not exists in the target array.");
}
return $key;
}
Here's a code example:
$array = array();
$array['master']['slave'] = "foo";
foreach ($array as $key => $value) {
foreach ($value as $key2 => $value2) {
if (preg_match('/slave/',$key2)) {
$value[$key2] = "bar";
print "$value[$key2] => $key2 => $value2\n";
}
}
}
print_r($array);
Output:
bar => slave => foo
Array
(
[master] => Array
(
[slave] => foo
)
)
Rather i would like to have the following as the final array:
Array
(
[master] => Array
(
[slave] => bar
)
)
What wrong am i doing here?
Thank you!
Note:
Example2:
$a= array('l1'=>array('l2'=>array('l3'=>array('l4'=>array('l5'=>'foo')))));
$a['l1']['l2']['l3']['l4']['l5'] = 'bar';
foreach ($a as $i => &$values) {
foreach ( $values as $key => &$value) {
if (is_array($value)){
print_array($value,$key);
}
}
}
function print_array ($Array, $parent) {
foreach ($Array as $i1 => &$values1) {
if (is_array($values1)){
foreach ($values1 as $key1 => &$value1) {
if (is_array($value1)) {
print_array($value1,$values1);
}
else {
print " $key1 => $value1\n";
}
}
}
else {
if (preg_match('/l5/',$i1)) {
$values1 = "foobar";
print " $i1 => $values1\n";
}
}
}
}
print_r($a);
Output does not reflect 'foobar' in l5
Because foreach operates on a copy of the array. Read the documentation about foreach:
Note: Unless the array is referenced, foreach operates on a copy of the specified array and not the array itself. foreach has some side effects on the array pointer. Don't rely on the array pointer during or after the foreach without resetting it.
So you should do
foreach ($array as $key => &$value) {
foreach ($value as $key2 => $value2) {
//...
}
}
Update:
Ok, I reviewed your code again:
Your code was not working as your loops never reach the array with key l5.
The code is highly inefficient. You make assumptions about the depth of the input array. E.g. your code cannot process the input array you provide (it should work if you omit one array).
Solution:
Make use of recursion. This code works:
$a =array('l1'=>array('l2'=>array('l3'=>array('l4'=>array('l5'=>'foo')))));
function process(&$array, $needle) {
foreach($array as $k => &$v) {
if ($k == $needle) {
$v = "boooooooooo";
print "$k => $v\n";
}
if (is_array($v)) {
process($v, $needle);
}
}
}
process($a, $needle);
print_r($a);
Hope that helps.
Oh and please use other keys next time. I thought the whole time that the key was 15 (fifteen) and was wondering why my example was not working ;) (15 looks not that different from l5 at a glance).
You have a few choices, but all stem from the same problem, which originates on this line
foreach ($array as $key => $value) {
At this point in the code, $value is not a reference to 2nd dimension of arrays in your data structure. To fix this, you have a couple options.
1) Force a reference
foreach ($array as $key => &$value) {
2) Use a "fully-qualified" expression to set the desired value
$array[$key][$key2] = 'bar';
Because $value is a new variable
Why not just:
foreach ($array as $key => &$value)
{
if(isset($value['slave']))
$value['slave'] = 'bar';
};