How to check whether an array is empty using PHP

Question

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

User · Answer

An empty array is falsey in PHP  so you don t even need to use empty   as others have suggested    lt  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

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If you just need to check if there are ANY elements in the array  if  empty  playerlist             list is empty      If you need to clean out empty values before checking  generally done to prevent explodeing weird strings    foreach   playerlist as  key   gt   value        if  empty  value            unset  playerlist  key            if  empty  playerlist          empty array

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If you d like to exclude the false or empty rows  such as 0   gt       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

User · Answer

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

User · Answer

This seems working for all cases  if  empty sizeof  array

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empty  gamerow  players

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count  gamerow  players    will be 0

User · Answer

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

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I ran the benchmark included at the end of the post  To compare the methods    count  arr     0   count empty  arr    empty  arr         comp  bool   arr   cast   and 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  lt  php        012345678  nt   90000000    arr0        arr1        arr2        arr3        arr4        arr5        for   i   0   i  lt  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  lt   nt   i          count  arr0     0     t01   microtime true   for   i   0   i  lt   nt   i          empty  arr0      t02   microtime true   for   i   0   i  lt   nt   i           arr0           t03   microtime true   for   i   0   i  lt   nt   i           bool   arr0     t04   microtime true     t10   microtime true   for   i   0   i  lt   nt   i          count  arr1     0     t11   microtime true   for   i   0   i  lt   nt   i          empty  arr1      t12   microtime true   for   i   0   i  lt   nt   i           arr1           t13   microtime true   for   i   0   i  lt   nt   i           bool   arr1     t14   microtime true       ------------------------------      t20   microtime true   for   i   0   i  lt   nt   i          count  arr2     0     t21   microtime true   for   i   0   i  lt   nt   i          empty  arr2      t22   microtime true   for   i   0   i  lt   nt   i           arr2           t23   microtime true   for   i   0   i  lt   nt   i           bool   arr2     t24   microtime true       ------------------------------      t30   microtime true   for   i   0   i  lt   nt   i          count  arr3     0     t31   microtime true   for   i   0   i  lt   nt   i          empty  arr3      t32   microtime true   for   i   0   i  lt   nt   i           arr3           t33   microtime true   for   i   0   i  lt   nt   i           bool   arr3     t34   microtime true       ------------------------------      t40   microtime true   for   i   0   i  lt   nt   i          count  arr4     0     t41   microtime true   for   i   0   i  lt   nt   i          empty  arr4      t42   microtime true   for   i   0   i  lt   nt   i           arr4           t43   microtime true   for   i   0   i  lt   nt   i           bool   arr4     t44   microtime true       -----------------------------------      t50   microtime true   for   i   0   i  lt   nt   i          count  arr5     0     t51   microtime true   for   i   0   i  lt   nt   i          empty  arr5      t52   microtime true   for   i   0   i  lt   nt   i           arr5           t53   microtime true   for   i   0   i  lt   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   gt   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   gt   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   gt   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   gt   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   gt   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   gt   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   gt   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

User · Answer

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

User · Answer

gamerow   mysql fetch array  gameresult    if   empty   gamerow  players           playerlist   explode       gamerow  players      else        do stuf if array is empty

User · Answer

is array  detect   amp  amp  empty  detect     is array

User · Answer

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

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Making the most appropriate decision requires knowing the quality of your data and what processes are to follow   If you are going to disqualify disregard remove this row  then the earliest point of filtration should be in the mysql query     WHERE players IS NOT NULL  WHERE players        WHERE COALESCE players             WHERE players IS NOT NULL AND players          it kind of depends on your store data and there will be other ways  I ll stop here    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  quot flexibility quot  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   I have whistleblown nearly every answer on this page and this answer is likely to draw revenge votes  this happens often to whistleblowers who defend this site -- if an answer has downvotes and no comments  always be skeptical   I think it is important that Stackoverflow is a trusted resource that doesn t poison researchers with misinformation and suboptimal techniques  This is how I show how much I care about upcoming developers so that they learn the how and the why instead of just spoon-feeding a generation of copy-paste programmers  I frequently use old pages to close new duplicate pages -- this is the responsibility of veteran volunteers who know how to quickly find duplicates   I cannot bring myself to use an old page with bad false suboptimal misleading information as a reference because then I am actively doing a disservice to a new researcher

User · Answer

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

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status    quot  quot     new array   array     if  empty  new array       status    quot 1 quot        not a blank array   else     status    quot 0 quot        blank array

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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

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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    gt   UserValueA    UserKeyB    gt   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 empty        ARRAY TWO     ArrayTwo is not empty        ARRAY 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 empty        ARRAY TWO     arraytwo is not empty        ARRAY 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

User · Answer

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- gt Front Category- gt get category detail  cat id    catArray    catDetail  allData    cat title      echo implode      catArray

User · Answer

Why has no one said this answer    array        if  array                 array is empty

[php] How to check whether an array is empty using PHP?

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