Remove empty array elements

Question

Some elements in my array are empty strings based on what the user has submitted  I need to remove those elements  I have this   foreach  linksArray as  link        if  link                      unset  link           print r  linksArray     But it doesn t work   linksArray still has empty elements  I have also tried doing it with the empty   function  but the outcome is the same

User · Answer

my     0   gt      1   gt  5   2   gt  6   3   gt           foreach   my as  key   gt   value        if  is null  value   unset  my  key       foreach   my as  key   gt   value        echo    key          value     lt br gt         output     1 5      2 6

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out array   array filter  input array  function  item          return  empty  item  key of array to check whether it is empty

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With these types of things  it s much better to be explicit about what you want and do not want   It will help the next guy to not get caught by surprise at the behaviour of array filter   without a callback  For example  I ended up on this question because I forgot if array filter   removes NULL or not  I wasted time when I could have just used the solution below and had my answer   Also  the logic is language angnostic in the sense that the code can be copied into another language without having to under stand the behaviour of a php function like array filter when no callback is passed   In my solution  it is clear at glance as to what is happening  Remove a conditional to keep something or add a new condition to filter additional values   Disregard the actual use of array filter   since I am just passing it a custom callback - you could go ahead and extract that out to its own function if you wanted  I am just using it as sugar for a foreach loop    lt  php   xs    0  1  2  3   0       false  null     xs   array filter  xs  function  x        if   x     null    return false        if   x     false    return false        if   x           return false        if   x      0     return false        return true        xs   array values  xs      reindex array     echo   lt pre gt    var export  xs     Another benefit of this approach is that you can break apart the filtering predicates into an abstract function that filters a single value per array and build up to a composable solution   See this example and the inline comments for the output    lt  php          param string  valueToFilter        return  Closure A function that expects a 1d array and returns an array                     filtered of values matching  valueToFilter      function filterValue  valueToFilter        return function  xs  use   valueToFilter            return array filter  xs  function  x  use   valueToFilter                return  x      valueToFilter                           partially applied functions that each expect a 1d array of values  filterNull   filterValue null    filterFalse   filterValue false    filterZeroString   filterValue  0     filterEmptyString   filterValue        xs    0  1  2  3  null  false   0          xs    filterNull  xs              gt   0  1  2  3  false   0        xs    filterFalse  xs             gt   0  1  2  3   0        xs    filterZeroString  xs        gt   0  1  2  3       xs    filterEmptyString  xs       gt   0  1  2  3   echo   lt pre gt    var export  xs       gt   0  1  2  3    Now you can dynamically create a function called filterer   using pipe   that will apply these partially applied functions for you    lt  php         Supply between 1  n functions each with an arity of 1  that is  accepts    one and only one argument   Versions prior to php 5 6 do not have the    variadic operator       and as such require the use of  func get args    to    obtain the comma-delimited list of expressions provided via the argument    list on function call        Example - Call the function  pipe    like          pipe   addOne   multiplyByTwo          return closure     function pipe          functions   func get args       an array of callable functions   addOne   multiplyByTwo      return function   initialAccumulator  use   functions       return a function with an arity of 1         return array reduce     chain the supplied   arg  value through each function in the list of functions              functions     an array of functions to reduce over the supplied   arg  value             function   accumulator   currFn       the reducer  a reducing function                  return  currFn  accumulator                               initialAccumulator                              param string  valueToFilter        return  Closure A function that expects a 1d array and returns an array                     filtered of values matching  valueToFilter      function filterValue  valueToFilter        return function  xs  use   valueToFilter            return array filter  xs  function  x  use   valueToFilter                return  x      valueToFilter                         filterer   pipe      filterValue null       filterValue false       filterValue  0        filterValue          xs    0  1  2  3  null  false   0         xs    filterer  xs    echo   lt pre gt    var export  xs       gt   0  1  2  3

User · Answer

foreach  linksArray as  key   gt   link          if  link                         unset  linksArray  key               print r  linksArray

User · Answer

You can use array filter to remove empty elements    emptyRemoved   array filter  linksArray     If you have  int  0 in your array  you may use the following    emptyRemoved   remove empty  linksArray    function remove empty  array      return array filter  array    remove empty internal       function  remove empty internal  value      return  empty  value      value     0      EDIT  Maybe your elements are not empty per se but contain one or more spaces    You can use the following before using array filter   trimmedArray   array map  trim    linksArray

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Just want to contribute an alternative to loops   also addressing gaps in keys     In my case I wanted to keep sequential array keys when the operation was complete  not just odd numbers  which is what I was staring at  Setting up code to look just for odd keys seemed fragile to me and not future-friendly    I was looking for something more like this  http   gotofritz net blog howto removing-empty-array-elements-php   The combination of array filter and array slice does the trick     example   array filter  example    example   array slice  example 0    No idea on efficiencies or benchmarks but it works

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try this       Example   or   array           PersonalInformation first name    gt   this- gt request- gt data  User    first name             PersonalInformation last name    gt   this- gt request- gt data  User    last name             PersonalInformation primary phone    gt   this- gt request- gt data  User    primary phone             PersonalInformation dob    gt   this- gt request- gt data  User    dob             User email    gt   this- gt request- gt data  User    email                or   array filter  or         condition   array           User role    gt  array  U    P             User user status    gt  array  active    lead    inactive             OR    gt   or

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The most popular answer on this topic is absolutely INCORRECT   Consider the following PHP script    lt  php  arr   array  1        2    3    0       Incorrect  print r array filter  arr       Correct  print r array filter  arr   strlen       Why is this   Because a string containing a single  0  character also evaluates to boolean false  so even though it s not an empty string  it will still get filtered   That would be a bug   Passing the built-in strlen function as the filtering function will work  because it returns a non-zero integer for a non-empty string  and a zero integer for an empty string   Non-zero integers always evaluate to true when converted to boolean  while zero integers always evaluate to false when converted to boolean   So  the absolute  definitive  correct answer is    arr   array filter  arr   strlen

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I use the following script to remove empty elements from an array  for   i 0   i lt  count  Array    i            if  empty  Array  i    unset  Array  i

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As you re dealing with an array of strings  you can simply use array filter    which conveniently handles all this for you   print r array filter  linksArray      Keep in mind that if no callback is supplied  all entries of array equal to FALSE  see converting to boolean  will be removed  So if you need to preserve elements that are i e  exact string  0   you will need a custom callback      PHP 7 4 and later print r array filter  linksArray  fn  value    gt   is null  value   amp  amp   value               PHP 5 3 and later print r array filter  linksArray  function  value    return  is null  value   amp  amp   value                  PHP  lt  5 3 print r array filter  linksArray  create function   value    return  value

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I had to do this in order to keep an array value of  string  0   url   array filter  data  function   value      return   empty  value      value     0     value    0

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Remove empty array elements  function removeEmptyElements  amp  element        if  is array  element             if   key   key  element                  element  key    array filter  element                      if  count  element     count  element  COUNT RECURSIVE                  element   array filter current  element     FUNCTION                        return  element        else           return empty  element    false    element            data   array       horarios    gt  array         grupos    gt  array           1A    gt  array               Juan    gt  array                   calificaciones    gt  array                       Matematicas    gt  8                       Espa  ol    gt  5                       Ingles    gt  9                                      asistencias    gt  array                       enero    gt  20                       febrero    gt  10                       marzo    gt                                                    Damian    gt  array                   calificaciones    gt  array                       Matematicas    gt  10                       Espa  ol    gt                           Ingles    gt  9                                      asistencias    gt  array                       enero    gt  20                       febrero    gt                           marzo    gt  5                                                       1B    gt  array               Mariana    gt  array                   calificaciones    gt  array                       Matematicas    gt  null                       Espa  ol    gt  7                       Ingles    gt  9                                      asistencias    gt  array                       enero    gt  null                       febrero    gt  5                       marzo    gt  5                                                         data   array filter  data   removeEmptyElements    var dump  data       it works

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Just one line   Update  thanks to  suther     array without empty values   array filter  array

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Another one liner to remove empty     empty string  elements from your array    array   array filter  array  function  a   return  a              Note  This code deliberately keeps null  0 and false elements     Or maybe you want to trim your array elements first    array   array filter  array  function  a        return trim  a                Note  This code also removes null and false elements

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use array filter function to remove empty values    linksArray   array filter  linksArray   print r  linksArray

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As per your method  you can just catch those elements in an another array and use that one like follows   foreach  linksArray as  link      if  empty  link           new arr      link         print r  new arr

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If you are working with a numerical array and need to re-index the array after removing empty elements  use the array values function   array values array filter  array      Also see  PHP reindex array

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You can just do  array filter  array    array filter   If no callback is supplied  all entries of input equal to FALSE will be removed   This means that elements with values NULL  0   0       FALSE  array   will be removed too   The other option is doing  array diff  array  array        which will remove elements with values NULL     and FALSE   Hope this helps     UPDATE  Here is an example    a   array 0   0   NULL  FALSE      array      var dump array filter  a       array    var dump array diff  a  array 0       0    0     array NULL  FALSE      array      var dump array diff  a  array NULL       NULL   FALSE         array 0   0   array      To sum up    0 or  0  will remove 0 and  0  NULL  FALSE or    will remove NULL  FALSE and

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linksArray   array filter  linksArray      If no callback is supplied  all entries of input equal to FALSE will be removed   -- http   php net manual en function array-filter php

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function trim array  Array        foreach   Array as  value            if trim  value                         index   array search  value   Array               unset  Array  index                        return  Array

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myarray   array filter  myarray   strlen       removes null values but leaves  0       myarray   array filter  myarray                removes all null values

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I think array walk is much more suitable here  linksArray   array  name                  342    0   0 0  null      false    array walk  linksArray  function  amp  v   k  use   amp  linksArray        v   trim  v       if   v                unset  linksArray  k        print r  linksArray    Output  Array        0    gt  name      2    gt  342      3    gt  0      4    gt  0     We made sure that empty values are removed even if the user adds more than one space  We also trimmed empty spaces from the valid values  Finally  only  null    Boolean False  and      will be considered empty strings   As for False it s ok to remove it  because AFAIK the user can t submit boolean values

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The most voted answer is wrong or at least not completely true as the OP is talking about blank strings only  Here s a thorough explanation  What does empty mean  First of all  we must agree on what empty means  Do you mean to filter out   the empty strings only   quot  quot    the strictly false values    element     false  the falsey values   i e  0  0 0   quot  quot    quot 0 quot   NULL  array       the equivalent of PHP s empty   function   How do you filter out the values To filter out empty strings only   filtered   array diff  originalArray  array  quot  quot      To only filter out strictly false values  you must use a callback function   filtered   array diff  originalArray   myCallback    function myCallback  var        return  var     false     The callback is also useful for any combination in which you want to filter out the  quot falsey quot  values  except some   For example  filter every null and false  etc  leaving only 0    filtered   array filter  originalArray   myCallback    function myCallback  var        return   var     0     var      0       Third and fourth case are  for our purposes at last  equivalent  and for that all you have to use is the default   filtered   array filter  originalArray

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In short   This is my suggested code    myarray    array values array filter array map  trim    myarray    strlen       Explanation   I thinks use array filter is good  but not enough  because values be like space and  n     keep in the array and this is usually bad   So I suggest you use mixture   array filter and array map   array map is for trimming  array filter is for remove empty values  strlen is for keep 0 value  and array values is for re indexing if you needed   Samples    myarray   array   r     n     r n             0    a          r     n     r n         a   new1   array filter  myarray        a   new2   array filter array map  trim    myarray         0    a   new3   array filter array map  trim    myarray    strlen         0    a   reindex   new4   array values array filter array map  trim    myarray    strlen      var dump  new1   new2   new3   new4     Results   array 5       0   gt    string 1       1   gt    string 1         2   gt    string 2         4   gt    string 1         6   gt    string 1   a    array 1       6   gt    string 1   a    array 2       5   gt    string 1   0     6   gt    string 1   a    array 2       0   gt    string 1   0     1   gt    string 1   a      Online Test   http   phpio net s 5yg0

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foreach  arr as  key   gt   val      if  empty  val   unset  arr  key

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a   array 1              2      3  4    b   array values array filter  a     print r  b

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For multidimensional array    data   array map  array filter    data    data   array filter  data

[php] Remove empty array elements

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