players will either be empty or a comma separated list (or a single value). What is the easiest way to check if it's empty? I'm assuming I can do so as soon as I fetch the $gameresult array into $gamerow? In this case it would probably be more efficient to skip exploding the $playerlist if it's empty, but for the sake of argument, how would I check if an array is empty as well?
$gamerow = mysql_fetch_array($gameresult);
$playerlist = explode(",", $gamerow['players']);
An empty array is falsey in PHP, so you don't even need to use empty() as others have suggested.
<?php
$playerList = array();
if (!$playerList) {
echo "No players";
} else {
echo "Explode stuff...";
}
// Output is: No players
PHP's empty() determines if a variable doesn't exist or has a falsey value (like array(), 0, null, false, etc).
In most cases you just want to check !$emptyVar. Use empty($emptyVar) if the variable might not have been set AND you don't wont to trigger an E_NOTICE; IMO this is generally a bad idea.
I have solved this issue with following code.
$catArray=array();
$catIds=explode(',',$member['cat_id']);
if(!empty($catIds[0])){
foreach($catIds as $cat_id){
$catDetail=$this->Front_Category->get_category_detail($cat_id);
$catArray[]=$catDetail['allData']['cat_title'];
}
echo implode(',',$catArray);
}
If you'd like to exclude the false or empty rows (such as 0 => ''), where using empty() will fail, you can try:
if (array_filter($playerlist) == []) {
// Array is empty!
}
array_filter(): If no callback is supplied, all entries of array equal to FALSE (see converting to boolean) will be removed.
If you'd like to remove all NULL, FALSE and empty strings (''), but leave zero values (0), you can use strlen as a callback, e.g.:
$is_empty = array_filter($playerlist, 'strlen') == [];
In my opinion the simplest way for an indexed array would be simply:
if ($array) {
//Array is not empty...
}
An 'if' condition on the array would evaluate to true if the array is not empty and false if the array is empty. This is not applicable to associative arrays.
$status = "";
$new_array = array();
if(!empty($new_array)){
$status = "1"; // not a blank array
}
else{
$status = "0"; // blank array
}
If you want to ascertain whether the variable you are testing is actually explicitly an empty array, you could use something like this:
if ($variableToTest === array()) {
echo 'this is explicitly an empty array!';
}
Why has no one said this answer:
$array = [];
if($array == []) {
// array is empty
}
if you are to check the array content you may use:
$arr = array();
if(!empty($arr)){
echo "not empty";
}
else
{
echo "empty";
}
see here: http://codepad.org/EORE4k7v
I ran the benchmark included at the end of the post. To compare the methods:
count($arr) == 0 : countempty($arr) : empty$arr == [] : comp(bool) $arr : castand got the following results
Contents \method | count | empty | comp | cast |
------------------|--------------|--------------|--------------|--------------|
Empty |/* 1.213138 */|/* 1.070011 */|/* 1.628529 */| 1.051795 |
Uniform |/* 1.206680 */| 1.047339 |/* 1.498836 */|/* 1.052737 */|
Integer |/* 1.209668 */|/* 1.079858 */|/* 1.486134 */| 1.051138 |
String |/* 1.242137 */| 1.049148 |/* 1.630259 */|/* 1.056610 */|
Mixed |/* 1.229072 */|/* 1.068569 */|/* 1.473339 */| 1.064111 |
Associative |/* 1.206311 */| 1.053642 |/* 1.480637 */|/* 1.137740 */|
------------------|--------------|--------------|--------------|--------------|
Total |/* 7.307005 */| 6.368568 |/* 9.197733 */|/* 6.414131 */|
The difference between empty and casting to a boolean are insignificant. I've run this test multiple times and they appear to be essentially equivalent. The contents of the arrays do not seem to play a significant role. The two produce the opposite results but the logical negation is barely enough to push casting to winning most of the time so I personally prefer empty for the sake of legibility in either case.
#!/usr/bin/php
<?php
// 012345678
$nt = 90000000;
$arr0 = [];
$arr1 = [];
$arr2 = [];
$arr3 = [];
$arr4 = [];
$arr5 = [];
for ($i = 0; $i < 500000; $i++) {
$arr1[] = 0;
$arr2[] = $i;
$arr3[] = md5($i);
$arr4[] = $i % 2 ? $i : md5($i);
$arr5[md5($i)] = $i;
}
$t00 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
count($arr0) == 0;
}
$t01 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
empty($arr0);
}
$t02 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
$arr0 == [];
}
$t03 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
(bool) $arr0;
}
$t04 = microtime(true);
$t10 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
count($arr1) == 0;
}
$t11 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
empty($arr1);
}
$t12 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
$arr1 == [];
}
$t13 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
(bool) $arr1;
}
$t14 = microtime(true);
/* ------------------------------ */
$t20 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
count($arr2) == 0;
}
$t21 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
empty($arr2);
}
$t22 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
$arr2 == [];
}
$t23 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
(bool) $arr2;
}
$t24 = microtime(true);
/* ------------------------------ */
$t30 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
count($arr3) == 0;
}
$t31 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
empty($arr3);
}
$t32 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
$arr3 == [];
}
$t33 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
(bool) $arr3;
}
$t34 = microtime(true);
/* ------------------------------ */
$t40 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
count($arr4) == 0;
}
$t41 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
empty($arr4);
}
$t42 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
$arr4 == [];
}
$t43 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
(bool) $arr4;
}
$t44 = microtime(true);
/* ----------------------------------- */
$t50 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
count($arr5) == 0;
}
$t51 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
empty($arr5);
}
$t52 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
$arr5 == [];
}
$t53 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
(bool) $arr5;
}
$t54 = microtime(true);
/* ----------------------------------- */
$t60 = $t00 + $t10 + $t20 + $t30 + $t40 + $t50;
$t61 = $t01 + $t11 + $t21 + $t31 + $t41 + $t51;
$t62 = $t02 + $t12 + $t22 + $t32 + $t42 + $t52;
$t63 = $t03 + $t13 + $t23 + $t33 + $t43 + $t53;
$t64 = $t04 + $t14 + $t24 + $t34 + $t44 + $t54;
/* ----------------------------------- */
$ts0[1] = number_format(round($t01 - $t00, 6), 6);
$ts0[2] = number_format(round($t02 - $t01, 6), 6);
$ts0[3] = number_format(round($t03 - $t02, 6), 6);
$ts0[4] = number_format(round($t04 - $t03, 6), 6);
$min_idx = array_keys($ts0, min($ts0))[0];
foreach ($ts0 as $idx => $val) {
if ($idx == $min_idx) {
$ts0[$idx] = " $val ";
} else {
$ts0[$idx] = "/* $val */";
}
}
$ts1[1] = number_format(round($t11 - $t10, 6), 6);
$ts1[2] = number_format(round($t12 - $t11, 6), 6);
$ts1[3] = number_format(round($t13 - $t12, 6), 6);
$ts1[4] = number_format(round($t14 - $t13, 6), 6);
$min_idx = array_keys($ts1, min($ts1))[0];
foreach ($ts1 as $idx => $val) {
if ($idx == $min_idx) {
$ts1[$idx] = " $val ";
} else {
$ts1[$idx] = "/* $val */";
}
}
$ts2[1] = number_format(round($t21 - $t20, 6), 6);
$ts2[2] = number_format(round($t22 - $t21, 6), 6);
$ts2[3] = number_format(round($t23 - $t22, 6), 6);
$ts2[4] = number_format(round($t24 - $t23, 6), 6);
$min_idx = array_keys($ts2, min($ts2))[0];
foreach ($ts2 as $idx => $val) {
if ($idx == $min_idx) {
$ts2[$idx] = " $val ";
} else {
$ts2[$idx] = "/* $val */";
}
}
$ts3[1] = number_format(round($t31 - $t30, 6), 6);
$ts3[2] = number_format(round($t32 - $t31, 6), 6);
$ts3[3] = number_format(round($t33 - $t32, 6), 6);
$ts3[4] = number_format(round($t34 - $t33, 6), 6);
$min_idx = array_keys($ts3, min($ts3))[0];
foreach ($ts3 as $idx => $val) {
if ($idx == $min_idx) {
$ts3[$idx] = " $val ";
} else {
$ts3[$idx] = "/* $val */";
}
}
$ts4[1] = number_format(round($t41 - $t40, 6), 6);
$ts4[2] = number_format(round($t42 - $t41, 6), 6);
$ts4[3] = number_format(round($t43 - $t42, 6), 6);
$ts4[4] = number_format(round($t44 - $t43, 6), 6);
$min_idx = array_keys($ts4, min($ts4))[0];
foreach ($ts4 as $idx => $val) {
if ($idx == $min_idx) {
$ts4[$idx] = " $val ";
} else {
$ts4[$idx] = "/* $val */";
}
}
$ts5[1] = number_format(round($t51 - $t50, 6), 6);
$ts5[2] = number_format(round($t52 - $t51, 6), 6);
$ts5[3] = number_format(round($t53 - $t52, 6), 6);
$ts5[4] = number_format(round($t54 - $t53, 6), 6);
$min_idx = array_keys($ts5, min($ts5))[0];
foreach ($ts5 as $idx => $val) {
if ($idx == $min_idx) {
$ts5[$idx] = " $val ";
} else {
$ts5[$idx] = "/* $val */";
}
}
$ts6[1] = number_format(round($t61 - $t60, 6), 6);
$ts6[2] = number_format(round($t62 - $t61, 6), 6);
$ts6[3] = number_format(round($t63 - $t62, 6), 6);
$ts6[4] = number_format(round($t64 - $t63, 6), 6);
$min_idx = array_keys($ts6, min($ts6))[0];
foreach ($ts6 as $idx => $val) {
if ($idx == $min_idx) {
$ts6[$idx] = " $val ";
} else {
$ts6[$idx] = "/* $val */";
}
}
echo " | count | empty | comp | cast |\n";
echo "-------------|--------------|--------------|--------------|--------------|\n";
echo " Empty |";
echo $ts0[1] . '|';
echo $ts0[2] . '|';
echo $ts0[3] . '|';
echo $ts0[4] . "|\n";
echo " Uniform |";
echo $ts1[1] . '|';
echo $ts1[2] . '|';
echo $ts1[3] . '|';
echo $ts1[4] . "|\n";
echo " Integer |";
echo $ts2[1] . '|';
echo $ts2[2] . '|';
echo $ts2[3] . '|';
echo $ts2[4] . "|\n";
echo " String |";
echo $ts3[1] . '|';
echo $ts3[2] . '|';
echo $ts3[3] . '|';
echo $ts3[4] . "|\n";
echo " Mixed |";
echo $ts4[1] . '|';
echo $ts4[2] . '|';
echo $ts4[3] . '|';
echo $ts4[4] . "|\n";
echo " Associative |";
echo $ts5[1] . '|';
echo $ts5[2] . '|';
echo $ts5[3] . '|';
echo $ts5[4] . "|\n";
echo "-------------|--------------|--------------|--------------|--------------|\n";
echo " Total |";
echo $ts6[1] . '|';
echo $ts6[2] . '|';
echo $ts6[3] . '|';
echo $ts6[4] . "|\n";
Some decent answers, but just thought I'd expand a bit to explain more clearly when PHP determines if an array is empty.
Main Notes:
An array with a key (or keys) will be determined as NOT empty by PHP.
As array values need keys to exist, having values or not in an array doesn't determine if it's empty, only if there are no keys (AND therefore no values).
So checking an array with empty() doesn't simply tell you if you have values or not, it tells you if the array is empty, and keys are part of an array.
So consider how you are producing your array before deciding which checking method to use.
EG An array will have keys when a user submits your HTML form when each form field has an array name (ie name="array[]").
A non empty array will be produced for each field as there will be auto incremented key values for each form field's array.
Take these arrays for example:
/* Assigning some arrays */
// Array with user defined key and value
$ArrayOne = array("UserKeyA" => "UserValueA", "UserKeyB" => "UserValueB");
// Array with auto increment key and user defined value
// as a form field would return with user input
$ArrayTwo[] = "UserValue01";
$ArrayTwo[] = "UserValue02";
// Array with auto incremented key and no value
// as a form field would return without user input
$ArrayThree[] = '';
$ArrayThree[] = '';
If you echo out the array keys and values for the above arrays, you get the following:
ARRAY ONE:
[UserKeyA] => [UserValueA]
[UserKeyB] => [UserValueB]ARRAY TWO:
[0] => [UserValue01]
[1] => [UserValue02]ARRAY THREE:
[0] => []
[1] => []
And testing the above arrays with empty() returns the following results:
ARRAY ONE:
$ArrayOne is not emptyARRAY TWO:
$ArrayTwo is not emptyARRAY THREE:
$ArrayThree is not empty
An array will always be empty when you assign an array but don't use it thereafter, such as:
$ArrayFour = array();
This will be empty, ie PHP will return TRUE when using if empty() on the above.
So if your array has keys - either by eg a form's input names or if you assign them manually (ie create an array with database column names as the keys but no values/data from the database), then the array will NOT be empty().
In this case, you can loop the array in a foreach, testing if each key has a value. This is a good method if you need to run through the array anyway, perhaps checking the keys or sanitising data.
However it is not the best method if you simply need to know "if values exist" returns TRUE or FALSE. There are various methods to determine if an array has any values when it's know it will have keys. A function or class might be the best approach, but as always it depends on your environment and exact requirements, as well as other things such as what you currently do with the array (if anything).
Here's an approach which uses very little code to check if an array has values:
Using array_filter():
Iterates over each value in the array passing them to the callback function. If the callback function returns true, the current value from array is returned into the result array. Array keys are preserved.
$EmptyTestArray = array_filter($ArrayOne);
if (!empty($EmptyTestArray))
{
// do some tests on the values in $ArrayOne
}
else
{
// Likely not to need an else,
// but could return message to user "you entered nothing" etc etc
}
Running array_filter() on all three example arrays (created in the first code block in this answer) results in the following:
ARRAY ONE:
$arrayone is not emptyARRAY TWO:
$arraytwo is not emptyARRAY THREE:
$arraythree is empty
So when there are no values, whether there are keys or not, using array_filter() to create a new array and then check if the new array is empty shows if there were any values in the original array.
It is not ideal and a bit messy, but if you have a huge array and don't need to loop through it for any other reason, then this is the simplest in terms of code needed.
I'm not experienced in checking overheads, but it would be good to know the differences between using array_filter() and foreach checking if a value is found.
Obviously benchmark would need to be on various parameters, on small and large arrays and when there are values and not etc.
WHERE players IS NOT NULL WHERE players != '' WHERE COALESCE(players, '') != '' WHERE players IS NOT NULL AND players != ''If you aren't 100% sure if the column will exist in the result set, then you should check that the column is declared. This will mean calling array_key_exists(), isset(), or empty() on the column. I am not going to bother delineating the differences here (there are other SO pages for that breakdown, here's a start: 1, 2, 3). That said, if you aren't in total control of the result set, then maybe you have over-indulged application "flexibility" and should rethink if the trouble of potentially accessing non-existent column data is worth it. Effectively, I am saying that you should never need to check if a column is declared -- ergo you should never need empty() for this task. If anyone is arguing that empty() is more appropriate, then they are pushing their own personal opinion about expressiveness of scripting. If you find the condition in #5 below to be ambiguous, add an inline comment to your code -- but I wouldn't. The bottom line is that there is no programmatical advantage to making the function call.
Might your string value contain a 0 that you want to deem true/valid/non-empty? If so, then you only need to check if the column value has length.
Here is a Demo using strlen(). This will indicated whether or not the string will create meaningful array elements if exploded.
I think it is important to mention that by unconditionally exploding, you are GUARANTEED to generate a non-empty array. Here's proof: Demo In other words, checking if the array is empty is completely useless -- it will be non-empty every time.
If your string will NOT POSSIBLY contain a zero value (because, say, this is a csv consisting of ids which start from 1 and only increment), then if ($gamerow['players']) { is all you need -- end of story.
...but wait, what are you doing after determining the emptiness of this value? If you have something down-script that is expecting $playerlist, but you are conditionally declaring that variable, then you risk using the previous row's value or again generating Notices. So do you need to unconditionally declare $playerlist as something? If there are no truthy values in the string, does your application benefit from declaring an empty array? Chances are, the answer is yes. In this case, you can ensure that the variable is array-type by falling back to an empty array -- this way it won't matter if you feed that variable into a loop. The following conditional declarations are all equivalent.
if ($gamerow['players']) { $playerlist = explode(',', $gamerow['players']); } else { $playerlist = []; }$playerlist = $gamerow['players'] ? explode(',', $gamerow['players']) : [];Why have I gone to such length to explain this very basic task?
$gamerow = mysql_fetch_array($gameresult);
if (!empty(($gamerow['players'])) {
$playerlist = explode(",", $gamerow['players']);
}else{
// do stuf if array is empty
}
I use this code
$variable = array();
if( count( $variable ) == 0 )
{
echo "Array is Empty";
}
else
{
echo "Array is not Empty";
}
But note that if the array has a large number of keys, this code will spend much time counting them, as compared to the other answers here.
is_array($detect) && empty($detect);
I think the best way to determine if the array is empty or not is to use count() like so:
if(count($array)) {
return 'anything true goes here';
}else {
return 'anything false';
}
empty($gamerow['players'])
This seems working for all cases
if(!empty(sizeof($array)))
You can use array_filter() which works great for all situations:
$ray_state = array_filter($myarray);
if (empty($ray_state)) {
echo 'array is empty';
} else {
echo 'array is not empty';
}
count($gamerow['players']) will be 0.
Source: Stackoverflow.com