There is an array of airports that gets filled with a user list.
$airport_array[$airport_row['airportICAO']] = array(
'airportName' => $airport_row['airportName'],
'airportCity' => $airport_row['airportCity'],
'airportLat' => $airport_row['airportLat'],
'airportLong' => $airport_row['airportLong'],
'airportUserCount' => 0,
'airportUserList' => array()
);
After filling, "airportUserCount" will either be 0 or higher than 1. Now, I want to remove all airports from the array where airportUserCount is set to 0. What is the most performant way to do it? I thought about a foreach loop but I fear it's not necessarily the most elegant solution.
Use this code
foreach($airport_array as $key=>$value){
if($value['airportUserCount']==0){
unset($airport_array[$key]);
}
}
Here is live demo : https://eval.in/608462
$new_airports = array_filter(
$old_airports,
function($a) { return 0 < $a['airportUserCount']; }
);
foreach loop, check for the ones that have the Count == 0 then remove them from the array.
$result = array();
foreach ($airport_array[$airport_row['airportICAO']] as $arrays)
{
if($arrays['airportUserCount'] == 0) {
array_push($result, $arrays);
}
}
Use array_filter:
$a = array_filter($a, function($v) { return $v['airportUserCount'] != 0; });
Demo :- https://eval.in/608464
array_filter allows you to iterate through an array while using a callback function to check values.
function filterAirports($airports){
return ($airport['airportUserCount'] == 0) ? true : false ;
}
print_r(array_filter($airport_array, "filterAirports"));
Related
$data = array
(
array("Ravi","Kuwait",350),
array("Sameer","UK",400),
array("Aditi","Switzerland",50),
array("Akshay","India",250),
array("rishi","Singapore",200),
array("Mukul","Ireland",100)
);
I want to put condition to the third row such that I can get entries of less than 300.
I suppose that you meant "the third element" in each nested array.Use array_filter function to get an array of elements, those third element's value is less than 300:
$result = array_filter($data, function($v) { return $v[2] < 300; });
print_r($result);
Try this code:
<?php
$data = array
(
array("Ravi","Kuwait",350),
array("Sameer","UK",400),
array("Aditi","Switzerland",50),
array("Akshay","India",250),
array("rishi","Singapore",200),
array("Mukul","Ireland",100)
);
$newArray = array();
foreach($data as $key => $value)
{
if($value[2] <= 100)
$newArray[] = $value;
}
print_r($newArray);
?>
You can achieve this using the PHP function array_filter() :
PHP
function limitArray($array) {
return ($array[2] <= 300);
}
print_r(array_filter($data, 'limitArray'));
evalIN
I`m using $_POST array with results of checkbox's selected from a form.
I'm thinking of using php in_array function but how could I extract only values that start with chk Given the following array:
Array (
[chk0] => 23934567622639616
[chk3] => 23934567622639618
[chk4] => 23934567622639619
[select-all] => on
[process] => Process
)
Thanks!
Simple and fast
$result=array();
foreach($_POST as $key => $value){
if(substr($key, 0, 2) == 'chk'){
$result[$key] = $value;
}
}
Lots of ways to do this, I like array_filter.
Example:
$result = array_filter(
$_POST,
function ($key) {
return strpos($key, "chk") === 0;
},
ARRAY_FILTER_USE_KEY
);
Here's a solution from http://php.net/manual/en/function.preg-grep.php
<?php
function preg_grep_keys($pattern, $input, $flags = 0) {
return array_intersect_key($input, array_flip(preg_grep($pattern, array_keys($input), $flags)));
}
?>
I would use array_filter
$ary = array_filter($originalArray,
function($key){ return preg_match('/chk/', $key); },
ARRAY_FILTER_USE_KEY
);
This question already has answers here:
How to check if PHP array is associative or sequential?
(60 answers)
Closed 9 years ago.
How do I find out if a PHP array was built like this:
array('First', 'Second', 'Third');
Or like this:
array('first' => 'First', 'second' => 'Second', 'third' => 'Third');
???
I have these simple functions in my handy bag o' PHP tools:
function is_flat_array($ar) {
if (!is_array($ar))
return false;
$keys = array_keys($ar);
return array_keys($keys) === $keys;
}
function is_hash($ar) {
if (!is_array($ar))
return false;
$keys = array_keys($ar);
return array_keys($keys) !== $keys;
}
I've never tested its performance on large arrays. I mostly use it on arrays with 10 or fewer keys so it's not usually an issue. I suspect it will have better performance than comparing $keys to the generated range 0..count($array).
print_r($array);
There is no difference between
array('First', 'Second', 'Third');
and
array(0 => 'First', 1 => 'Second', 2 => 'Third');
The former just has implicit keys rather than you specifying them
programmatically, you can't. I suppose the only way to check in a case like yours would be to do something like:
foreach ($myarray as $key => $value) {
if ( is_numeric($key) ) {
echo "the array appears to use numeric (probably a case of the first)";
}
}
but this wouldn't detect the case where the array was built as $array = array(0 => "first", 1 => "second", etc);
function is_assoc($array) {
return (is_array($array)
&& (0 !== count(array_diff_key($array, array_keys(array_keys($array))))
|| count($array)==0)); // empty array is also associative
}
here's another
function is_assoc($array) {
if ( is_array($array) && ! empty($array) ) {
for ( $i = count($array) - 1; $i; $i-- ) {
if ( ! array_key_exists($i, $array) ) { return true; }
}
return ! array_key_exists(0, $array);
}
return false;
}
Gleefully swiped from the is_array comments on the PHP documentation site.
That's a little tricky, especially that this form array('First', 'Second', 'Third'); implicitly lets PHP generate keys values.
I guess a valid workaround would go something like:
function array_indexed( $array )
{
$last_k = -1;
foreach( $array as $k => $v )
{
if( $k != $last_k + 1 )
{
return false;
}
$last_k++;
}
return true;
}
If you have php > 5.1 and are only looking for 0-based arrays, you can shrink the code to
$stringKeys = array_diff_key($a, array_values($a));
$isZeroBased = empty($stringKeys);
I Hope this will help you
Jerome WAGNER
function isAssoc($arr)
{
return $arr !== array_values($arr);
}
Is it possible to use array_map() to test values of an array? I want to make sure that all elements of an array are numeric.
I've tried both
$arrays = array(
array(0,1,2,3 )
, array ( 0,1, "a", 5 )
);
foreach ( $arrays as $arr ) {
if ( array_map("is_numeric", $arr) === FALSE ) {
echo "FALSE\n";
} else {
echo "TRUE\n";
}
}
and
$arrays = array(
array(0,1,2,3 )
, array ( 0,1, "a", 5 )
);
foreach ( $arrays as $arr ) {
if ( ( array_map("is_numeric", $arr) ) === FALSE ) {
echo "FALSE\n";
} else {
echo "TRUE\n";
}
}
And for both I get
TRUE
TRUE
Can this be done? If so, what am I doing wrong?
Note: I am aware that I can get my desired functionality from a foreach loop.
array_map returns an array. So it will always be considered 'true'. Now, if you array_search for FALSE, you might be able to get the desire effects.
From the PHP.net Page
array_map() returns an array containing all the elements of
arr1 after applying the callback function to each one.
This means that currently you have an array that contains true or false for each element. You would need to use array_search(false,$array) to find out if there are any false values.
I'm usually a big advocate of array_map(), array_filter(), etc., but in this case foreach() is going to be the best choice. The reason is that with array_map() and others it will go through the entire array no matter what. But for your purposes you only need to go through the array until you run into a value for which is_numeric() returns false, and as far as I know there's no way in PHP to break out of those methods.
In other words, if you have 1,000 items in your array and the 5th one isn't numeric, using array_map() will still check the remaining 995 values even though you already know the array doesn't pass your test. But if you use a foreach() instead and have it break on is_numeric() == false, then you'll only need to check those first five elements.
You could use filter, but it ends up with a horrible bit of code
$isAllNumeric = count(array_filter($arr, "is_numeric")) === count($arr)
Using a custom function makes it a bit better, but still not perfect
$isAllNumeric = count(array_filter($arr, function($x){return !is_numeric($x);})) === 0
But if you were using custom functions array_reduce would work, but it still has some failings.
$isAllNumeric = array_reduce($arr,
function($x, $y){ return $x && is_numeric($y); },
true);
The failings are that it won't break when it has found what it wants, so the functional suggestions above are not very efficient. You would need to write a function like this:
function array_find(array $array, $callback){
foreach ($array as $x){ //using iteration as PHP fails at recursion
if ( call_user_func($callback, array($x)) ){
return $x;
}
}
return false;
}
And use it like so
$isAllNumeric = array_find($arr, function($x){return !is_numeric($x);})) !== false;
i have two tiny but extremely useful functions in my "standard library"
function any($ary, $func) {
foreach($ary as $val)
if(call_user_func($func, $val)) return true;
return false;
}
function all($ary, $func) {
foreach($ary as $val)
if(!call_user_func($func, $val)) return false;
return true;
}
in your example
foreach ( $arrays as $arr )
echo all($arr, 'is_numeric') ? "ok" : "not ok";
A more elegant approach IMHO:
foreach ($arrays as $array)
{
if (array_product(array_map('is_numeric', $array)) == true)
{
echo "TRUE\n";
}
else
{
echo "FALSE\n";
}
}
This will return true if all the values are numeric and false if any of the values is not numeric.
What is the most efficient way to check if an array is a flat array
of primitive values or if it is a multidimensional array?
Is there any way to do this without actually looping through an
array and running is_array() on each of its elements?
Use count() twice; one time in default mode and one time in recursive mode. If the values match, the array is not multidimensional, as a multidimensional array would have a higher recursive count.
if (count($array) == count($array, COUNT_RECURSIVE))
{
echo 'array is not multidimensional';
}
else
{
echo 'array is multidimensional';
}
This option second value mode was added in PHP 4.2.0. From the PHP Docs:
If the optional mode parameter is set to COUNT_RECURSIVE (or 1), count() will recursively count the array. This is particularly useful for counting all the elements of a multidimensional array. count() does not detect infinite recursion.
However this method does not detect array(array()).
The short answer is no you can't do it without at least looping implicitly if the 'second dimension' could be anywhere. If it has to be in the first item, you'd just do
is_array($arr[0]);
But, the most efficient general way I could find is to use a foreach loop on the array, shortcircuiting whenever a hit is found (at least the implicit loop is better than the straight for()):
$ more multi.php
<?php
$a = array(1 => 'a',2 => 'b',3 => array(1,2,3));
$b = array(1 => 'a',2 => 'b');
$c = array(1 => 'a',2 => 'b','foo' => array(1,array(2)));
function is_multi($a) {
$rv = array_filter($a,'is_array');
if(count($rv)>0) return true;
return false;
}
function is_multi2($a) {
foreach ($a as $v) {
if (is_array($v)) return true;
}
return false;
}
function is_multi3($a) {
$c = count($a);
for ($i=0;$i<$c;$i++) {
if (is_array($a[$i])) return true;
}
return false;
}
$iters = 500000;
$time = microtime(true);
for ($i = 0; $i < $iters; $i++) {
is_multi($a);
is_multi($b);
is_multi($c);
}
$end = microtime(true);
echo "is_multi took ".($end-$time)." seconds in $iters times\n";
$time = microtime(true);
for ($i = 0; $i < $iters; $i++) {
is_multi2($a);
is_multi2($b);
is_multi2($c);
}
$end = microtime(true);
echo "is_multi2 took ".($end-$time)." seconds in $iters times\n";
$time = microtime(true);
for ($i = 0; $i < $iters; $i++) {
is_multi3($a);
is_multi3($b);
is_multi3($c);
}
$end = microtime(true);
echo "is_multi3 took ".($end-$time)." seconds in $iters times\n";
?>
$ php multi.php
is_multi took 7.53565130424 seconds in 500000 times
is_multi2 took 4.56964588165 seconds in 500000 times
is_multi3 took 9.01706600189 seconds in 500000 times
Implicit looping, but we can't shortcircuit as soon as a match is found...
$ more multi.php
<?php
$a = array(1 => 'a',2 => 'b',3 => array(1,2,3));
$b = array(1 => 'a',2 => 'b');
function is_multi($a) {
$rv = array_filter($a,'is_array');
if(count($rv)>0) return true;
return false;
}
var_dump(is_multi($a));
var_dump(is_multi($b));
?>
$ php multi.php
bool(true)
bool(false)
For PHP 4.2.0 or newer:
function is_multi($array) {
return (count($array) != count($array, 1));
}
I think this is the most straight forward way and it's state-of-the-art:
function is_multidimensional(array $array) {
return count($array) !== count($array, COUNT_RECURSIVE);
}
After PHP 7 you could simply do:
public function is_multi(array $array):bool
{
return is_array($array[array_key_first($array)]);
}
You could look check is_array() on the first element, under the assumption that if the first element of an array is an array, then the rest of them are too.
I think you will find that this function is the simplest, most efficient, and fastest way.
function isMultiArray($a){
foreach($a as $v) if(is_array($v)) return TRUE;
return FALSE;
}
You can test it like this:
$a = array(1 => 'a',2 => 'b',3 => array(1,2,3));
$b = array(1 => 'a',2 => 'b');
echo isMultiArray($a) ? 'is multi':'is not multi';
echo '<br />';
echo isMultiArray($b) ? 'is multi':'is not multi';
Don't use COUNT_RECURSIVE
click this site for know why
use rsort and then use isset
function is_multi_array( $arr ) {
rsort( $arr );
return isset( $arr[0] ) && is_array( $arr[0] );
}
//Usage
var_dump( is_multi_array( $some_array ) );
Even this works
is_array(current($array));
If false its a single dimension array if true its a multi dimension array.
current will give you the first element of your array and check if the first element is an array or not by is_array function.
You can also do a simple check like this:
$array = array('yo'=>'dream', 'mydear'=> array('anotherYo'=>'dream'));
$array1 = array('yo'=>'dream', 'mydear'=> 'not_array');
function is_multi_dimensional($array){
$flag = 0;
while(list($k,$value)=each($array)){
if(is_array($value))
$flag = 1;
}
return $flag;
}
echo is_multi_dimensional($array); // returns 1
echo is_multi_dimensional($array1); // returns 0
I think this one is classy (props to another user I don't know his username):
static public function isMulti($array)
{
$result = array_unique(array_map("gettype",$array));
return count($result) == 1 && array_shift($result) == "array";
}
In my case. I stuck in vary strange condition.
1st case = array("data"=> "name");
2nd case = array("data"=> array("name"=>"username","fname"=>"fname"));
But if data has array instead of value then sizeof() or count() function not work for this condition. Then i create custom function to check.
If first index of array have value then it return "only value"
But if index have array instead of value then it return "has array"
I use this way
function is_multi($a) {
foreach ($a as $v) {
if (is_array($v))
{
return "has array";
break;
}
break;
}
return 'only value';
}
Special thanks to Vinko Vrsalovic
Its as simple as
$isMulti = !empty(array_filter($array, function($e) {
return is_array($e);
}));
This function will return int number of array dimensions (stolen from here).
function countdim($array)
{
if (is_array(reset($array)))
$return = countdim(reset($array)) + 1;
else
$return = 1;
return $return;
}
Try as follows
if (count($arrayList) != count($arrayList, COUNT_RECURSIVE))
{
echo 'arrayList is multidimensional';
}else{
echo 'arrayList is no multidimensional';
}
$is_multi_array = array_reduce(array_keys($arr), function ($carry, $key) use ($arr) { return $carry && is_array($arr[$key]); }, true);
Here is a nice one liner. It iterates over every key to check if the value at that key is an array. This will ensure true