1. Check if all values are equal without knowing the values from array: $array = array('true', 'true', 'true'); if((count(array_unique($array)) === 1)) { echo "all equal"; } else { echo "not equal"; } 2. Check if all values are equal when you know the value from array: - In this case we know the equal value should be "true" $array = array('true', 'true', 'true'); if (count(array_unique($array)) === 1 && end($array) === 'true') { }
4.11. Checking if an Element Is in an Array
Problem
You want to know if an array contains a certain value.
Solution
Use in_array( ) :
if (in_array($value, $array)) { // an element has $value as its value in array $array }Discussion
Use in_array( ) to check if an element of an array holds a value:
$book_collection = array('Emma', 'Pride and Prejudice', 'Northhanger Abbey'); $book = 'Sense and Sensibility'; if (in_array($book, $book_collection) { echo 'Own it.'; } else { echo 'Need it.'; }The default behavior of in_array( ) is to compare items using the == operator. To use the strict equality check, ===, pass true as the third parameter to in_array( ):
$array = array(1, '2', 'three'); in_array(0, $array); // true! in_array(0, $array, true); // false in_array(1, $array); // true in_array(1, $array, true); // true in_array(2, $array); // true in_array(2, $array, true); // falseThe first check, in_array(0, $array), evaluates to true because to compare the number 0 against the string three, PHP casts three to an integer. Since three isn’t a numeric string, as is 2, it becomes 0. Therefore, in_array( ) thinks there’s a match.
Consequently, when comparing numbers against data that may contain strings, it’s safest to use a strict comparison.
If you find yourself calling in_array( ) multiple times on the same array, it may be better to use an associative array, with the original array elements as the keys in the new associative array. Looking up entries using in_array( ) takes linear time; with an associative array, it takes constant time.
If you can’t create the associative array directly but need to convert from a traditional one with integer keys, use array_flip( ) to swap the keys and values of an array:
$book_collection = array('Emma', 'Pride and Prejudice', 'Northhanger Abbey'); // convert from numeric array to associative array $book_collection = array_flip($book_collection); $book = 'Sense and Sensibility'; if (isset($book_collection[$book])) { echo 'Own it.'; } else { echo 'Need it.'; }Note that doing this condenses multiple keys with the same value into one element in the flipped array.
Is there any simple way to check if all values in an array are same with an simple if condition
Something like
if( ...some code...) { //yes, all values are same } else { //nope, all are not same }
my PHP Version is 5.2.9-2
Any help would be appreciated.
Basically, i want to check if values in an array are equals to 1.
(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)
array_intersect — Computes the intersection of arrays
Description
array_intersect(array $array, array ...$arrays): array
Parameters
arrayThe array with master values to check.
arraysArrays to compare values against.
Return Values
Returns an array containing all of the values in array whose values exist in all of the parameters.
Changelog
| 8.0.0 | This function can now be called with only one parameter. Formerly, at least two parameters have been required. |
Examples
Example #1 array_intersect() example
<?php
$array1 = array("a" => "green", "red", "blue");
$array2 = array("b" => "green", "yellow", "red");
$result = array_intersect($array1, $array2);
print_r($result);
?>
The above example will output:
Array ( [a] => green [0] => red )
Notes
Note: Two elements are considered equal if and only if (string) $elem1 === (string) $elem2. In words: when the string representation is the same.
See Also
- array_intersect_assoc() - Computes the intersection of arrays with additional index check
- array_diff() - Computes the difference of arrays
- array_diff_assoc() - Computes the difference of arrays with additional index check
stuart at horuskol dot co dot uk ¶
14 years ago
A clearer example of the key preservation of this function:
<?php
$array1
= array(2, 4, 6, 8, 10, 12);$array2 = array(1, 2, 3, 4, 5, 6);var_dump(array_intersect($array1, $array2));
var_dump(array_intersect($array2, $array1));?>
yields the following:
array(3) {
[0]=> int(2)
[1]=> int(4)
[2]=> int(6)
}
array(3) {
[1]=> int(2)
[3]=> int(4)
[5]=> int(6)
}
This makes it important to remember which way round you passed the arrays to the function if these keys are relied on later in the script.
Niels ¶
16 years ago
Here is a array_union($a, $b):
<?php
// $a = 1 2 3 4
$union = // $b = 2 4 5 6
array_merge(
array_intersect($a, $b), // 2 4
array_diff($a, $b), // 1 3
array_diff($b, $a) // 5 6
); // $u = 1 2 3 4 5 6
?>
Shawn Pyle ¶
13 years ago
array_intersect handles duplicate items in arrays differently. If there are duplicates in the first array, all matching duplicates will be returned. If there are duplicates in any of the subsequent arrays they will not be returned.
<?php
array_intersect(array(1,2,2),array(1,2,3)); //=> array(1,2,2)
array_intersect(array(1,2,3),array(1,2,2)); //=> array(1,2)
?>
sapenov at gmail dot com ¶
17 years ago
If you need to supply arbitrary number of arguments
to array_intersect() or other array function,
use following function:
$full=call_user_func_array('array_intersect', $any_number_of_arrays_here);
blu at dotgeek dot org ¶
17 years ago
Note that array_intersect and array_unique doesnt work well with multidimensional arrays.
If you have, for example,
<?php
$orders_today
[0] = array('John Doe', 'PHP Book');$orders_today[1] = array('Jack Smith', 'Coke');$orders_yesterday[0] = array('Miranda Jones', 'Digital Watch');
$orders_yesterday[1] = array('John Doe', 'PHP Book');
$orders_yesterday[2] = array('Z? da Silva', 'BMW Car');?>
and wants to know if the same person bought the same thing today and yesterday and use array_intersect($orders_today, $orders_yesterday) you'll get as result:
<?phpArray
(
[0] => Array
(
[0] => John Doe
[1] => PHP Book
)
[
1] => Array(
[0] => Jack Smith
[1] => Coke
)
)
?>but we can get around that by serializing the inner arrays:
<?php
$orders_today
[0] = serialize(array('John Doe', 'PHP Book'));$orders_today[1] = serialize(array('Jack Smith', 'Coke'));$orders_yesterday[0] = serialize(array('Miranda Jones', 'Digital Watch'));
$orders_yesterday[1] = serialize(array('John Doe', 'PHP Book'));
$orders_yesterday[2] = serialize(array('Z? da Silva', 'Uncle Tungsten'));?>
so that array_map("unserialize", array_intersect($orders_today, $orders_yesterday)) will return:
<?phpArray
(
[0] => Array
(
[0] => John Doe
[1] => PHP Book
)
)
?>showing us who bought the same thing today and yesterday =)
[]s
yuval at visualdomains dot com ¶
7 years ago
Using isset to achieve this, is many times faster:
<?php
$m
= range(1,1000000);$s = [2,4,6,8,10];// Use array_intersect to return all $m values that are also in $s
$tstart = microtime(true);
print_r (array_intersect($m,$s));
$tend = microtime(true);
$time = $tend - $tstart;
echo "Took $time";// Use array_flip and isset to return all $m values that are also in $s
$tstart = microtime(true);
$f = array_flip($s);
/* $f now looks like this:
(
[2] => 0
[4] => 1
[6] => 2
[8] => 3
[10] => 4
)
*/
// $u will hold the intersected values
$u = [];
foreach ($m as $v) {
if (isset($f[$v])) $u[] = $v;
}
print_r ($u);
$tend = microtime(true);
$time = $tend - $tstart;
echo "Took $time";
?>
Results:
Array
(
[1] => 2
[3] => 4
[5] => 6
[7] => 8
[9] => 10
)
Took 4.7170009613037
(
[0] => 2
[1] => 4
[2] => 6
[3] => 8
[4] => 10
)
Took 0.056024074554443
array_intersect: 4.717
array_flip+isset: 0.056
dml at nm dot ru ¶
11 years ago
The built-in function returns wrong result when input arrays have duplicate values.
Here is a code that works correctly:
<?php
function array_intersect_fixed($array1, $array2) {
$result = array();
foreach ($array1 as $val) {
if (($key = array_search($val, $array2, TRUE))!==false) {
$result[] = $val;
unset($array2[$key]);
}
}
return $result;
}
?>
matang dot dave at gmail dot com ¶
7 years ago
Take care of value types while using array_intersect function as there is no option for strict type check as in in_array function.
$array1 = array(true,2);
$array2 = array(1, 2, 3, 4, 5, 6);
var_dump(array_intersect($array1, $array2));
result is :
array(2) {
[0] => bool(true)
[1] => int(2)
}
Oto Brglez ¶
13 years ago
If you wish to create intersection with arrays that are empty. Than the result of intersection is empty array.
If you wish to change this. I sugest that you do this.
It simply "ignores" empty arrays. Before loop use 1st array.
<?php
$a
= array();$a[] = 1;
$a[] = 2;
$a[] = 3;$b = array();
$b[] = 4;
$b[] = 5;
$b[] = 1;$c = array();
$c[] = 1;
$c[] = 5;
$d = array();$kb=array('a','b','c','d');$out = $a;
foreach($kb as $k){
if(!empty(${$k})) $out = array_intersect($out,${$k});
};
print_r($out);
// The result is array
// The result is empty array
print_r(array_intersect($a,$b,$c,$d));?>info at iridsystem dot it ¶
7 years ago
This function is able to sort an array based on another array that contains the order of occurrence. The values that are not present will be transferred into the end of the resultant.
Questa funzione permette di ordinare i valori di un array ($tosort) basandosi sui valori contenuti in un secondo array ($base), i valori non trovati verranno posizionati alla fine dell'ordinamento senza un'ordine specifico.
<?
$base= array('one', 'two', 'three');
$tosort= array('a'=>'two', 'b'=>'three', 'c'=>'five', 'd'=>'one', 'and'=>'four', 'f'=>'one');
uasort($tosort, function($key1, $key2) use ($base) {
$a1=array_search($key1, $base);
$a2=array_search($key2, $base);
if ( $a1===false && $a2===false ) { return 0; }
else if ( $a1===false && $a2 !== false) { return 1; }
else if ( $a1!==false && $a2 === false) {return -1;}
if( $a1 > $a2 ) { return 1; }
else if ( $a1 < $a2 ) { return -1; }
else if ( $a1 == $a2 ) { return 0; }
});
var_dump($tosort);
/*
the resulting of $tosort
array
'd' => string 'one' (length=3)
'f' => string 'one' (length=3)
'a' => string 'two' (length=3)
'b' => string 'three' (length=3)
'c' => string 'five' (length=6)
'e' => string 'four' (length=7)
*/
Gabriel
?>
Esfandiar -- e.bandari at gmail dot com ¶
14 years ago
Regarding array union: Here is a faster version array_union($a, $b)
But it is not needed! See below.
<?php
// $a = 1 2 3 4
$union = // $b = 2 4 5 6
array_merge(
$a,
array_diff($b, $a) // 5 6
); // $u = 1 2 3 4 5 6
?>
You get the same result with $a + $b.
N.B. for associative array the results of $a+$b and $b+$a are different, I think array_diff_key is used.
Cheers, E
theking at king dot ma ¶
4 months ago
I use array_intersect for a quick check of $_GET parameters;
<?php declare(strict_types=1)$_params = ['cust_id','prod_id'];
$_params_check = array_intersect(array_keys($_GET),$_params);
if(count($_params_check) !== count($_params)) {
header("HTTP/1.1 400 Bad Request");
die();
}
?>
the file will die with a 400 error if cust_id or prod_id or both are missing from $_GET. But i could be used on $_POST and $_REQUEST as well obviously.
Anonymous ¶
1 year ago
array_intersect use Value, not callback
array_uintersect use Value, callback receives Value
array_intersect_key use Key, not callback
array_intersect_ukey use Key, callback receives Key
array_intersect_assoc use Both, not callback
array_intersect_uassoc use Both, callback receives Key ONLY
array_uintersect_assoc use Both, callback receives Value ONLY
array_uintersect_uassoc use Both, One callback receives the Key, the other receives the Value.
Yohann ¶
12 years ago
I used array_intersect in order to sort an array arbitrarly:
<?php
$a = array('one', 'two', 'three', 'four', 'five', 'six', 'seven', 'height', 'nine', 'ten');
$b = array('four', 'one', 'height', 'five')
var_dump(array_intersect($a, $b);
?>
will output:
0 => 'one'
1 => 'four'
2 => 'five'
3 => 'height'
i hope this can help...
Malte ¶
14 years ago
Extending the posting by Terry from 07-Feb-2006 04:42:
If you want to use this function with arrays which have sometimes the same value several times, it won't be checked if they're existing in the second array as much as in the first.
So I delete the value in the second array, if it's found there:
<?php
$firstarray = array(1, 1, 2, 3, 4, 1);
$secondarray = array(4, 1, 6, 5, 4, 1);//array_intersect($firstarray, $secondarray): 1, 1, 1, 4foreach ($firstarray as $key=>$value){
if (!in_array($value,$secondarray)){
unset($firstarray[$key]);
}else{
unset($secondarray[array_search($value,$secondarray)]);
}
}//$firstarray: 1, 1, 4?>
nthitz at gmail dot com ¶
16 years ago
I did some trials and if you know the approximate size of the arrays then it would seem to be a lot faster to do this <?php array_intersect($smallerArray, $largerArray); ?> Where $smallerArray is the array with lesser items. I only tested this with long strings but I would imagine that it is somewhat universal.
t dot wiltzius at insightbb dot com ¶
18 years ago
I needed to compare an array with associative keys to an array that contained some of the keys to the associative array. Basically, I just wanted to return only a few of the entries in the original array, and the keys to the entries I wanted were stored in another array. This is pretty straightforward (although complicated to explain), but I couldn't find a good function for comparing values to keys. So I wrote this relatively straightforward one:
<?phpfunction key_values_intersect($values,$keys) {
foreach($keys AS $key) {
$key_val_int[$key] = $values[$key];
}
return $key_val_int;
}$big = array("first"=>2,"second"=>7,"third"=>3,"fourth"=>5);
$subset = array("first","third");print_r(key_values_intersect($big,$subset));?>
This will return:
Array ( [first] => 2 [third] => 3 )
anbolb at boltblue dot com ¶
18 years ago
This is also handy for testing an array for one of a series of acceptable elements. As a simple example, if you're expecting the query string to contain one of, say, user_id, order_id or item_id, to find out which one it is you could do this:
<?php
$valid_ids = array ('user_id', 'item_id', 'order_id');
if ($id = current (array_intersect ($valid_ids, array_keys ($_GET))))
{
// do some stuff with it
}
else
// error - invalid id passed, or none at all
?>
...which could be useful for constructing an SQL query, or some other situation where testing for them one by one might be too clumsy.
terry(-at-)shuttleworths(-dot-)net ¶
16 years ago
I couldn't get array_intersect to work with two arrays of identical objects, so I just did this:
foreach ($firstarray as $key=>$value){
if (!in_array($value,$secondarray)){
unset($firstarray[$key]);
}
}
This leaves $firstarray as the intersection.
Seems to work fine & reasonably quickly.
tom p ¶
16 years ago
If you store a string of keys in a database field and want to match them to a static array of values, this is a quick way to do it without loops:
<?
$vals = array("Blue","Green","Pink","Yellow");
$db_field = "0,2,3";
echo implode(", ", array_flip(array_intersect(array_flip($vals), explode(",", $db_field))));
// will output "Blue, Pink, Yellow"
?>
caffinated ¶
9 years ago
If you're looking for a relatively easy way to strictly intersect keys and values recursively without array key reordering, here's a simple recursive function:
<?php
function array_intersect_recursive($array1, $array2)
{
foreach($array1 as $key => $value)
{
if (!isset($array2[$key]))
{
unset($array1[$key]);
}
else
{
if (is_array($array1[$key]))
{
$array1[$key] = array_intersect_recursive($array1[$key], $array2[$key]);
}
elseif ($array2[$key] !== $value)
{
unset($array1[$key]);
}
}
}
return $array1;
}
?>
ben at kazez dot com ¶
18 years ago
To check whether an array $a is a subset of array $b, do the following:
<?php
if(array_unique($b + $a) === $b)
//...
?>
Actually, PHP ought to have a function that does this for you. But the above example works.
Mike Block ¶
9 years ago
I bench-marked some uses of array_intersect and can't believe how slow it is. This isn't as elaborate, but handles most cases and is much faster:
<?php
/**
examines two arrays and returns the intersected arrays with matching keys (ignores duplicate keys)
*/
function simple_array_intersect($a,$b) {
$a_assoc = $a != array_values($a);
$b_assoc = $b != array_values($b);
$ak = $a_assoc ? array_keys($a) : $a;
$bk = $b_assoc ? array_keys($b) : $b;
$out = array();
for ($i=0;$i<sizeof($ak);$i++) {
if (in_array($ak[$i],$bk)) {
if ($a_assoc) {
$out[$ak[$i]] = $a[$ak[$i]];
} else {
$out[] = $ak[$i];
}
}
}
return $out;
}?>
You can try this out with this:
<?php
// create a large array (simple)
$first = array();
for ($i=500;$i<500000;$i++) {
$first[] = $i;
}
// create a smaller array (associative)
$second = array();
for ($i=499990;$i<500000;$i++) {
$second[$i] = rand();
}
echo microtime(true)."\n";
// built-in function
print_r(array_intersect($first,$second));
echo microtime(true)."\n";
// favour simple array as match
print_r(simple_array_intersect($first,$second));
echo microtime(true)."\n";
// favour associative keys for match
print_r(simple_array_intersect($second,$first));
echo microtime(true)."\n";?>
david at audiogalaxy dot com ¶
21 years ago
Note that array_intersect() considers the type of the array elements when it compares them.
If array_intersect() doesn't appear to be working, check your inputs using var_dump() to make sure you're not trying to intersect an array of integers with an array of strings.
gary ¶
13 years ago
i wrote this one to get over the problem i found in getting strings intersected instead of arrays as there is no function in php.
<?php
function matched_main_numbers($string, $string2)
{
$string = "04 16 17 20 29";
$arr1 = explode(" ", $string);
$string2 = "45 34 04 29 16";
$arr2 = explode(" ", $string2);
$array = array_intersect($arr1, $arr2);
$comma_separated = implode($array);
$str = $comma_separated;
$balls = "$comma_separated";
$matched_balls = chunk_split($balls,2," ");
$matched_balls =" $matched_balls";
$number_of_matched_main_balls = strlen($str);
$number_of_matched_main_balls = ($number_of_matched_main_balls/2);
$numbers = "You matched $number_of_matched_main_balls main balls";
return
$numbers;}
?>meihao at 126 dot com ¶
8 years ago
<?php
$a=array(1,2,'3',4);
$b=array('1',2,3);var_dump($a,$b);result:
array (size=3)
0 => int 1
1 => int 2
2 => string '3' (length=1)?>
Ehsan.Chavoshi.com ¶
3 years ago
I wrote this function to recursively replace array keys with array values (flip) and fill values with defined value. it can be used for recursive array intersect functions .
<?php
function array_values_to_keys_r($array, $fill_value = null)
{
$flipped = [];
foreach ($array as $key => $value) {
if (is_array($value)) {
$flipped [$key] = array_values_to_keys_r($value);
} else {
$flipped [$value] = $fill_value;
}
}
return $flipped;
}
?>
zoolyka at gmail dot com ¶
4 years ago
If you have to intersect arrays of unique values then using array_intersect_key is about 20 times faster, just have to flip the key value pairs of the arrays, then flip the result again.
<?php
$one
= range(1, 250000);$two = range(50000, 150000);$start = microtime(true);$intersection = array_intersect($one, $two);
echo
"Did it in ".( microtime(true) - $start )." seconds.\n";$start = microtime(true);$intersection = array_flip(array_intersect_key(array_flip($one), array_flip($two)));echo
"Did it in ".( microtime(true) - $start )." seconds.\n";?>Did it in 0.89163708686829 seconds.
Did it in 0.038213968276978 seconds.
ram ¶
4 years ago
$x = array('', 'ram', '');
$y = array('1231231231');
$result=array_intersect($x,$z);
$res = array_intersect($y, $z);
karl at libsyn dot com ¶
13 years ago
Given a multidimensional array that represents AND/OR relationships (example below), you can use a recursive function with array_intersect() to see if another array matches that set of relationships.
For example: array( array( 'red' ), array( 'white', 'blue' ) ) represents "red OR ( white AND blue )". array( 'red', array( 'white', 'blue' ) ) would work, too, BTW.
If I have array( 'red' ) and I want to see if it matches the AND/OR array, I use the following function. It returns the matched array,
but can just return a boolean if that's all you need:
<?php
$needle = array( array( 'red' ), array( 'white', 'blue' ) );
$haystack = array( 'red' );
function
findMatchingArray( $needle, $haystack ) {foreach( $needle as $element ) {
$test_element = (array) $element;
if( count( $test_element ) == count( array_intersect( $test_element, $haystack ) ) ) {
return $element;
}
}
return
}
?>
Pretty tough to describe what I needed it to do, but it worked. I don't know if anyone else out there needs something like this, but hope this helps.
189780 at gmail dot com ¶
12 years ago
Actually array_intersect finds the dublicate values, here is my approach which is 5 times faster than built-in function array_intersect().. Give a try..
<?php
function my_array_intersect($a,$b)
{
for($i=0;$i<sizeof($a);$i++)
{
$m[]=$a[$i];
}
for($i=0;$i<sizeof($a);$i++)
{
$m[]=$b[$i];
}
sort($m);
$get=array();
for($i=0;$i<sizeof($m);$i++)
{
if($m[$i]==$m[$i+1])
$get[]=$m[$i];
}
return $get;
}
?>
Barış ÇUHADAR
jake ¶
5 years ago
Also note that, even without the availability of the strict mode switch, false does not match 0:
array_intersect([false], [0]) == [];
Even in PHP 7.1