Deleting an element from an array in PHP

Question

Is there an easy way to delete an element from an array using PHP  such that foreach   array  no longer includes that element   I thought that setting it to null would do it  but apparently it does not work

User · Answer

For those of you who are looking for Ruby's hash#delete equivalent in PHP:

<?php
    function array_delete(&$array, $key) {
        if (!isset($array[$key])) {
            return null;
        }

        $value = $array[$key];
        unset($array[$key]);
        return $value;
    }

This will not only delete the element from your array, but it will also return the value stored in that key so you can consume your array in a non-linear fashion.

User · Answer

Use the following code    arr   array  orange    banana    apple    raspberry     result   array pop  arr   print r  result

User · Answer

x   array 1  2  3  4  5   var dump  x   unset  x 3       Here is the key to be deleted echo   lt br gt    array values  x   var dump  x

User · Answer

Solutions    To delete one element  use unset       unset  array 3    unset  array  foo         To delete multiple noncontiguous elements  also use unset       unset  array 3    array 5    unset  array  foo     array  bar         To delete multiple contiguous elements  use array splice       array splice  array   offset   length      Further explanation   Using these functions removes all references to these elements from PHP  If you want to keep a key in the array  but with an empty value  assign the empty string to the element    array 3     array  foo           Besides syntax  there s a logical difference between using unset   and assigning    to the element  The first says This doesn t exist anymore  while the second says This still exists  but its value is the empty string   If you re dealing with numbers  assigning 0 may be a better alternative  So  if a company stopped production of the model XL1000 sprocket  it would update its inventory with   unset  products  XL1000       However  if it temporarily ran out of XL1000 sprockets  but was planning to receive a new shipment from the plant later this week  this is better    products  XL1000     0    If you unset   an element  PHP adjusts the array so that looping still works correctly  It doesn t compact the array to fill in the missing holes  This is what we mean when we say that all arrays are associative  even when they appear to be numeric  Here s an example      Create a  numeric  array  animals   array  ant    bee    cat    dog    elk    fox    print  animals 1       Prints  bee  print  animals 2       Prints  cat  count  animals         Returns 6     unset   unset  animals 1       Removes element  animals 1     bee  print  animals 1       Prints    and throws an E NOTICE error print  animals 2       Still prints  cat  count  animals         Returns 5  even though  array 5  is  fox      Add a new element  animals       gnu      Add a new element  not Unix  print  animals 1       Prints     still empty print  animals 6       Prints  gnu   this is where  gnu  ended up count  animals         Returns 6     Assign     animals 2             Zero out value print  animals 2       Prints    count  animals         Returns 6  count does not decrease   To compact the array into a densely filled numeric array  use array values      animals   array values  animals     Alternatively  array splice   automatically reindexes arrays to avoid leaving holes      Create a  numeric  array  animals   array  ant    bee    cat    dog    elk    fox    array splice  animals  2  2   print r  animals   Array        0    gt  ant      1    gt  bee      2    gt  elk      3    gt  fox     This is useful if you re using the array as a queue and want to remove items from the queue while still allowing random access  To safely remove the first or last element from an array  use array shift   and array pop    respectively

User · Answer

unset doesn t change the index  but array splice does    arrayName   array  1    gt   somevalue                       2    gt   somevalue1                       3    gt   somevalue3                      500   gt   somevalue500                              echo  arrayName  500          somevalue500     array splice  arrayName  1  2        print r  arrayName         Array    0    gt  somevalue  1    gt  somevalue500          arrayName   array   1    gt   somevalue                            2    gt   somevalue1                            3    gt   somevalue3                           500   gt   somevalue500                                  echo  arrayName  500          somevalue500     unset  arrayName 1         print r  arrayName         Array    0    gt  somevalue  1    gt  somevalue500

User · Answer

Use the following code    arr   array  orange    banana    apple    raspberry     result   array pop  arr   print r  result

User · Answer

lt  php      stack     fruit1    fruit2    fruit3    fruit4         fruit   array shift  stack       print r  stack        echo  fruit    gt    Output           0    gt  fruit2      1    gt  fruit3      2    gt  fruit4    fruit1

User · Answer

Remove an array element based on a key   Use the unset function like below    a   array          salam           10          1     unset  a 1     print r  a            Output           Array                        0    gt  salam              2    gt  1                 Remove an array element based on value   Use the array search function to get an element key and use the above manner to remove an array element like below    a   array          salam           10          1      key   array search 10   a    if   key     false        unset  a  key       print r  a            Output           Array                        0    gt  salam              2    gt  1

User · Answer

If you have to delete multiple values in an array and the entries in that array are objects or structured data   array filter  1  is your best bet  Those entries that return a true from the callback function will be retained     array           x   gt 1  y   gt 2  z   gt 3          x   gt 2  y   gt 4  z   gt 6          x   gt 3  y   gt 6  z   gt 9       results   array filter  array  function  value        return  value  x    gt  2           gt     x   gt 3  y   gt 6 z  gt  9

User · Answer

Use array search to get the key and remove it with unset if found   if    key   array search  word    array       false        unset  array  key

User · Answer

I came here because I wanted to see if there was a more elegant solution to this problem than using unset  arr  i     To my disappointment these answers are either wrong or do not cover every edge case  Here is why array diff   does not work   Keys are unique in the array  while elements are not always unique   arr    1 2 2 3    foreach  arr as  i   gt   n        b   array diff  arr   n        echo  quot  n quot  json encode  b      Results     2 2 3   1 3   1 2 2    If two elements are the same they will be remove   This also applies for array search   and array flip    I saw a lot of answers with array slice   and array splice    but these functions only work with numeric arrays   All the answers I am aware if here does not answer the question  and so here is a solution that will work   arr    1 2 3    foreach  arr as  i   gt   n        b   array merge array slice  arr 0  i  array slice  arr  i 1        echo  quot  n quot  json encode  b      Results      2 3    1 3    1 2    Since unset  arr  i   will work on both associative array and numeric arrays this still does not answer the question  This solution is to compare the keys and with a tool that will handle both numeric and associative arrays  I use array diff uassoc   for this   This function compares the keys in a call back function   arr    1 2 2 3      arr     a   gt  z   b   gt  y   c   gt  x   d   gt  w    foreach  arr as  key   gt   n        b   array diff uassoc  arr    key  gt  n   function  a  b            if  a     b               return 1                        echo  quot  n quot  json encode  b          Results       2 2 3    1 2 3    1 2 2      b   gt  y   c   gt  x   d   gt  w      a   gt  z   c   gt  x   d   gt  w      a   gt  z   b   gt  y   d   gt  w      a   gt  z   b   gt  y   c   gt  x

User · Answer

unset  array  index

User · Answer

lt  php        If you want to remove a particular array element use this method      my array   array  key1   gt  value 1    key2   gt  value 2    key3   gt  value 3         print r  my array       if  array key exists  key1    my array             unset  my array  key1             print r  my array             else           echo  Key does not exist           gt    lt  php       To remove first array element      my array   array  key1   gt  value 1    key2   gt  value 2    key3   gt  value 3        print r  my array        new array   array slice  my array  1       print r  new array     gt     lt  php     echo   lt br  gt               To remove first array element to length        starts from first and remove two element      my array   array  key1   gt  value 1    key2   gt  value 2    key3   gt  value 3        print r  my array        new array   array slice  my array  1  2       print r  new array     gt         Output   Array    key1    gt  value 1  key2    gt  value 2  key3    gt   value 3   Array       key2    gt  value 2  key3    gt  value 3    Array    key1    gt  value 1  key2    gt  value 2  key3    gt  value 3    Array    key2    gt  value 2  key3    gt  value 3    Array    key1    gt  value 1  key2    gt  value 2  key3    gt  value 3    Array    key2    gt  value 2  key3    gt  value 3

User · Answer

unset  array  index

User · Answer

It should be noted that unset   will keep indexes untouched  which is what you d expect when using string indexes  array as hashtable   but can be quite surprising when dealing with integer indexed arrays    array   array 0  1  2  3   unset  array 2    var dump  array      array 3       0   gt    int 0     1   gt    int 1     3   gt    int 3         array   array 0  1  2  3   array splice  array  2  1   var dump  array      array 3       0   gt    int 0     1   gt    int 1     2   gt    int 3         So array splice   can be used if you d like to normalize your integer keys  Another option is using array values   after unset      array   array 0  1  2  3    unset  array 2     array   array values  array   var dump  array      array 3       0   gt    int 0     1   gt    int 1     2   gt    int 3

User · Answer

It should be noted that unset   will keep indexes untouched  which is what you d expect when using string indexes  array as hashtable   but can be quite surprising when dealing with integer indexed arrays    array   array 0  1  2  3   unset  array 2    var dump  array      array 3       0   gt    int 0     1   gt    int 1     3   gt    int 3         array   array 0  1  2  3   array splice  array  2  1   var dump  array      array 3       0   gt    int 0     1   gt    int 1     2   gt    int 3         So array splice   can be used if you d like to normalize your integer keys  Another option is using array values   after unset      array   array 0  1  2  3    unset  array 2     array   array values  array   var dump  array      array 3       0   gt    int 0     1   gt    int 1     2   gt    int 3

User · Answer

arrayName   array   1    gt   somevalue                        2    gt   somevalue1                        3    gt   somevalue3                         print r  arrayName 1       somevalue unset  arrayName 1     print r  arrayName

User · Answer

Destroy a single element of an array  unset     array1   array  A    B    C    D    E    unset  array1 2       Delete known index 2  value from array var dump  array1     The output will be   array 4       0   gt    string 1   A     1   gt    string 1   B     3   gt    string 1   D     4   gt    string 1   E      If you need to re index the array    array1   array values  array1   var dump  array1     Then the output will be   array 4       0   gt    string 1   A     1   gt    string 1   B     2   gt    string 1   D     3   gt    string 1   E      Pop the element off the end of array - return the value of the removed element  mixed array pop array  amp  array    stack   array  orange    banana    apple    raspberry     last fruit   array pop  stack   print r  stack   print r  Last Fruit    last fruit      Last element of the array   The output will be  Array        0    gt  orange      1    gt  banana      2    gt  apple   Last Fruit  raspberry   Remove the first element  red  from an array  - return the value of the removed element  mixed array shift   array  amp  array     color   array  a    gt   red    b    gt   green     c    gt   blue     first color   array shift  color   print r   color   print r   First Color     first color     The output will be   Array        b    gt  green      c    gt  blue   First Color  red

User · Answer

There are different ways to delete an array element  where some are more useful for some specific tasks than others  Deleting a single array element If you want to delete just one array element you can use unset   or alternatively  array splice    If you know the value and don   t know the key to delete the element you can use  array search   to get the key  This only works if the element does not occur more than once  since  array search returns the first hit only  unset   Note that when you use unset   the array keys won   t change  If you want to reindex the keys you can use  array values   after unset    which will convert all keys to numerically enumerated keys starting from 0  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot    unset  array 1                   Key which you want to delete  Output         0    gt  a      2    gt  c     array splice   method If you use  array splice   the keys will automatically be reindexed  but the associative keys won   t change     as opposed to  array values    which will convert all keys to numerical keys   array splice   needs the offset  not the key  as the second parameter  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot     array splice  array  1  1                           Offset which you want to delete  Output         0    gt  a      1    gt  c    array splice    same as unset    take the array by reference  You don   t assign the return values of those functions back to the array  Deleting multiple array elements If you want to delete multiple array elements and don   t want to call unset   or  array splice   multiple times you can use the functions  array diff   or  array diff key   depending on whether you know the values or the keys of the elements which you want to delete   array diff   method If you know the values of the array elements which you want to delete  then you can use  array diff    As before with unset   it won   t change the keys of the array  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot   3   gt   quot c quot     array    array diff  array    quot a quot    quot c quot                                   --------                               Array values which you want to delete  Output         1    gt  b     array diff key   method If you know the keys of the elements which you want to delete  then you want to use  array diff key    You have to make sure you pass the keys as keys in the second parameter and not as values  Keys won   t reindex  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot     array    array diff key  array   0   gt   quot xy quot    quot 2 quot    gt   quot xy quot                                                                                       Array keys which you want to delete  Output         1    gt  b    If you want to use unset   or  array splice   to delete multiple elements with the same value you can use  array keys   to get all the keys for a specific value and then delete all elements

User · Answer

Remove an array element based on a key   Use the unset function like below    a   array          salam           10          1     unset  a 1     print r  a            Output           Array                        0    gt  salam              2    gt  1                 Remove an array element based on value   Use the array search function to get an element key and use the above manner to remove an array element like below    a   array          salam           10          1      key   array search 10   a    if   key     false        unset  a  key       print r  a            Output           Array                        0    gt  salam              2    gt  1

User · Answer

key   array search  needle   array   if   key     false        unset  array  key

User · Answer

You can use the array pop method to remove the last element of an array    lt  php      a   array  one    two    Three        array pop  a       print r  a     gt  The out put will be Array    0    gt  one 1    gt  two    which deletes only last element of an array LIFO operation

User · Answer

There are different ways to delete an array element  where some are more useful for some specific tasks than others  Deleting a single array element If you want to delete just one array element you can use unset   or alternatively  array splice    If you know the value and don   t know the key to delete the element you can use  array search   to get the key  This only works if the element does not occur more than once  since  array search returns the first hit only  unset   Note that when you use unset   the array keys won   t change  If you want to reindex the keys you can use  array values   after unset    which will convert all keys to numerically enumerated keys starting from 0  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot    unset  array 1                   Key which you want to delete  Output         0    gt  a      2    gt  c     array splice   method If you use  array splice   the keys will automatically be reindexed  but the associative keys won   t change     as opposed to  array values    which will convert all keys to numerical keys   array splice   needs the offset  not the key  as the second parameter  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot     array splice  array  1  1                           Offset which you want to delete  Output         0    gt  a      1    gt  c    array splice    same as unset    take the array by reference  You don   t assign the return values of those functions back to the array  Deleting multiple array elements If you want to delete multiple array elements and don   t want to call unset   or  array splice   multiple times you can use the functions  array diff   or  array diff key   depending on whether you know the values or the keys of the elements which you want to delete   array diff   method If you know the values of the array elements which you want to delete  then you can use  array diff    As before with unset   it won   t change the keys of the array  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot   3   gt   quot c quot     array    array diff  array    quot a quot    quot c quot                                   --------                               Array values which you want to delete  Output         1    gt  b     array diff key   method If you know the keys of the elements which you want to delete  then you want to use  array diff key    You have to make sure you pass the keys as keys in the second parameter and not as values  Keys won   t reindex  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot     array    array diff key  array   0   gt   quot xy quot    quot 2 quot    gt   quot xy quot                                                                                       Array keys which you want to delete  Output         1    gt  b    If you want to use unset   or  array splice   to delete multiple elements with the same value you can use  array keys   to get all the keys for a specific value and then delete all elements

User · Answer

Associative arrays  For associative arrays  use unset    arr   array  a    gt  1   b    gt  2   c    gt  3   unset  arr  b         RESULT  array  a    gt  1   c    gt  3      Numeric arrays  For numeric arrays  use array splice    arr   array 1  2  3   array splice  arr  1  1       RESULT  array 0   gt  1  1   gt  3    Note  Using unset for numeric arrays will not produce an error  but it will mess up your indexes    arr   array 1  2  3   unset  arr 1        RESULT  array 0   gt  1  2   gt  3

User · Answer

unset   multiple  fragmented elements from an array  While unset   has been mentioned here several times  it has yet to be mentioned that unset   accepts multiple variables making it easy to delete multiple  noncontiguous elements from an array in one operation      Delete multiple  noncontiguous elements from an array  array      foo    bar    baz    quz     unset   array 2    array 3     print r  array      Output     foo    bar      unset   dynamically  unset   does not accept an array of keys to remove  so the code below will fail  it would have made it slightly easier to use unset   dynamically though     array   range 0 5    remove    1 2    array   unset   remove       FAILS   unexpected  unset   print r  array     Instead  unset   can be used dynamically in a foreach loop    array   range 0 5    remove    1 2   foreach   remove as  k  gt  v        unset  array  v      print r  array      Output    0  3  4  5     Remove array keys by copying the array  There is also another practice that has yet to be mentioned  Sometimes  the simplest way to get rid of certain array keys is to simply copy  array1 into  array2    array1   range 1 10   foreach   array1 as  v           Remove all even integers from the array     if   v   2              array2      v          print r  array2      Output    1  3  5  7  9      Obviously  the same practice applies to text strings    array1      foo     bar    baz     foreach   array1 as  v           Remove all strings beginning with underscore     if  strpos  v        false              array2      v          print r  array2      Output     foo    baz

User · Answer

lt  php      stack     fruit1    fruit2    fruit3    fruit4         fruit   array shift  stack       print r  stack        echo  fruit    gt    Output           0    gt  fruit2      1    gt  fruit3      2    gt  fruit4    fruit1

User · Answer

Use unset to delete the key Street     lt  php      arr1   array  Name    gt   Johm    Street    gt   Waall    Country    gt   India                        unset  arr1  Street                      gt    RESULT     array  Name    gt   Johm   Country    gt   India      This will not re-index the array after deleting the value  so use array splice

User · Answer

lt  php      array   array  your array         array   array diff  array    element you want to delete       gt    Create your array in the variable  array and then where I have put  element you want to delete  you put something like   a   And if you want to delete multiple items then   a    b

User · Answer

if you want to remove a specific object of an array by reference of that object you can do following   unset  array array search  object  array       Example    lt  php class Foo       public  id      public  name      foo1   new Foo     foo1- gt id   1   foo1- gt name    Name1     foo2   new Foo     foo2- gt id   2   foo2- gt name    Name2     foo3   new Foo     foo3- gt id   3   foo3- gt name    Name3      array   array  foo1  foo2  foo3   unset  array array search  foo2  array      echo   lt pre gt    var dump  array   echo   lt  pre gt      gt    Result   array 2     0   gt      object Foo  1  2              id    gt          int 1            name    gt          string 5   Name1         2   gt      object Foo  3  2              id    gt          int 3            name    gt          string 5   Name3            Note that if the object occures several times it will only be removed the first occurence

User · Answer

I d just like to say I had a particular object that had variable attributes  it was basically mapping a table and I was changing the columns in the table  so the attributes in the object  reflecting the table would vary as well    class obj       protected  fields   array  field1   field2        protected  field1   array        protected  field2   array        protected loadfields            This will load the  field1 and  field2 with rows of data for the column they describe     protected function clearFields  num           foreach  fields as  field                unset  this- gt  field  num                   This did not work the line below worked             unset  this- gt   field   num       You have to resolve  field first using                        The whole purpose of  fields was just  so I don t have to look everywhere in the code when they re changed  I just look at the beginning of the class and change the list of attributes and the  fields array content to reflect the new attributes

User · Answer

Associative arrays  For associative arrays  use unset    arr   array  a    gt  1   b    gt  2   c    gt  3   unset  arr  b         RESULT  array  a    gt  1   c    gt  3      Numeric arrays  For numeric arrays  use array splice    arr   array 1  2  3   array splice  arr  1  1       RESULT  array 0   gt  1  1   gt  3    Note  Using unset for numeric arrays will not produce an error  but it will mess up your indexes    arr   array 1  2  3   unset  arr 1        RESULT  array 0   gt  1  2   gt  3

User · Answer

For those of you who are looking for Ruby's hash#delete equivalent in PHP:

<?php
    function array_delete(&$array, $key) {
        if (!isset($array[$key])) {
            return null;
        }

        $value = $array[$key];
        unset($array[$key]);
        return $value;
    }

This will not only delete the element from your array, but it will also return the value stored in that key so you can consume your array in a non-linear fashion.

User · Answer

Use array search to get the key and remove it with unset if found   if    key   array search  word    array       false        unset  array  key

User · Answer

Use unset to delete the key Street     lt  php      arr1   array  Name    gt   Johm    Street    gt   Waall    Country    gt   India                        unset  arr1  Street                      gt    RESULT     array  Name    gt   Johm   Country    gt   India      This will not re-index the array after deleting the value  so use array splice

User · Answer

It should be noted that unset   will keep indexes untouched  which is what you d expect when using string indexes  array as hashtable   but can be quite surprising when dealing with integer indexed arrays    array   array 0  1  2  3   unset  array 2    var dump  array      array 3       0   gt    int 0     1   gt    int 1     3   gt    int 3         array   array 0  1  2  3   array splice  array  2  1   var dump  array      array 3       0   gt    int 0     1   gt    int 1     2   gt    int 3         So array splice   can be used if you d like to normalize your integer keys  Another option is using array values   after unset      array   array 0  1  2  3    unset  array 2     array   array values  array   var dump  array      array 3       0   gt    int 0     1   gt    int 1     2   gt    int 3

User · Answer

key   array search  needle   array   if   key     false        unset  array  key

User · Answer

unset  array  index

User · Answer

To avoid doing a search one can play around with array diff    array   array 3  9  11  20    array   array diff  array  array 11        removes 11   In this case one doesn t have to search use the key

User · Answer

Two ways for removing the first item of an array with keeping order of the index and also if you don t know the key name of the first item   Solution  1     1 is the index of the first object to get    NULL to get everything until the end    true to preserve keys  array   array slice  array  1  null  true     Solution  2     Rewinds the array s internal pointer to the first element    and returns the value of the first array element   value   reset  array      Returns the index element of the current array position  key   key  array   unset  array  key        For this sample data    array   array 10   gt   a   20   gt   b   30   gt   c      You must have this result   array 2       20   gt    string 1   b     30   gt    string 1   c

User · Answer

It should be noted that unset   will keep indexes untouched  which is what you d expect when using string indexes  array as hashtable   but can be quite surprising when dealing with integer indexed arrays    array   array 0  1  2  3   unset  array 2    var dump  array      array 3       0   gt    int 0     1   gt    int 1     3   gt    int 3         array   array 0  1  2  3   array splice  array  2  1   var dump  array      array 3       0   gt    int 0     1   gt    int 1     2   gt    int 3         So array splice   can be used if you d like to normalize your integer keys  Another option is using array values   after unset      array   array 0  1  2  3    unset  array 2     array   array values  array   var dump  array      array 3       0   gt    int 0     1   gt    int 1     2   gt    int 3

User · Answer

If the index is specified   arr     a    b    c     index   0      unset  arr  index         arr     b    c    If the index is NOT specified   arr     a    b    c     index   array search  a    arr      search the value to find index if  index     false      unset  arr  index         arr     b    c      The if condition is necessary because if index is not found  unset   will automatically delete the first element of the array which is not what we want

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There are different ways to delete an array element  where some are more useful for some specific tasks than others  Deleting a single array element If you want to delete just one array element you can use unset   or alternatively  array splice    If you know the value and don   t know the key to delete the element you can use  array search   to get the key  This only works if the element does not occur more than once  since  array search returns the first hit only  unset   Note that when you use unset   the array keys won   t change  If you want to reindex the keys you can use  array values   after unset    which will convert all keys to numerically enumerated keys starting from 0  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot    unset  array 1                   Key which you want to delete  Output         0    gt  a      2    gt  c     array splice   method If you use  array splice   the keys will automatically be reindexed  but the associative keys won   t change     as opposed to  array values    which will convert all keys to numerical keys   array splice   needs the offset  not the key  as the second parameter  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot     array splice  array  1  1                           Offset which you want to delete  Output         0    gt  a      1    gt  c    array splice    same as unset    take the array by reference  You don   t assign the return values of those functions back to the array  Deleting multiple array elements If you want to delete multiple array elements and don   t want to call unset   or  array splice   multiple times you can use the functions  array diff   or  array diff key   depending on whether you know the values or the keys of the elements which you want to delete   array diff   method If you know the values of the array elements which you want to delete  then you can use  array diff    As before with unset   it won   t change the keys of the array  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot   3   gt   quot c quot     array    array diff  array    quot a quot    quot c quot                                   --------                               Array values which you want to delete  Output         1    gt  b     array diff key   method If you know the keys of the elements which you want to delete  then you want to use  array diff key    You have to make sure you pass the keys as keys in the second parameter and not as values  Keys won   t reindex  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot     array    array diff key  array   0   gt   quot xy quot    quot 2 quot    gt   quot xy quot                                                                                       Array keys which you want to delete  Output         1    gt  b    If you want to use unset   or  array splice   to delete multiple elements with the same value you can use  array keys   to get all the keys for a specific value and then delete all elements

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If you need to remove multiple elements from an associative array  you can use array diff key    here used with array flip       my array   array     key1    gt   value 1      key2    gt   value 2      key3    gt   value 3      key4    gt   value 4      key5    gt   value 5        to remove   array  key2    key4      result   array diff key  my array  array flip  to remove     print r  result     Output   Array    key1    gt  value 1  key3    gt  value 3  key5    gt  value 5

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Two ways for removing the first item of an array with keeping order of the index and also if you don t know the key name of the first item   Solution  1     1 is the index of the first object to get    NULL to get everything until the end    true to preserve keys  array   array slice  array  1  null  true     Solution  2     Rewinds the array s internal pointer to the first element    and returns the value of the first array element   value   reset  array      Returns the index element of the current array position  key   key  array   unset  array  key        For this sample data    array   array 10   gt   a   20   gt   b   30   gt   c      You must have this result   array 2       20   gt    string 1   b     30   gt    string 1   c

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Also  for a named element   unset  array  elementName

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Suppose you have the following array   Array        user id    gt  193      storage    gt  5     To delete storage  do   unset  attributes  storage      attributes   array filter  attributes     And you get   Array        user id    gt  193

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You can simply use unset   to delete an array   Remember that an array must be unset after the foreach function

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Also  for a named element   unset  array  elementName

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If the index is specified   arr     a    b    c     index   0      unset  arr  index         arr     b    c    If the index is NOT specified   arr     a    b    c     index   array search  a    arr      search the value to find index if  index     false      unset  arr  index         arr     b    c      The if condition is necessary because if index is not found  unset   will automatically delete the first element of the array which is not what we want

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If you need to remove multiple elements from an associative array  you can use array diff key    here used with array flip       my array   array     key1    gt   value 1      key2    gt   value 2      key3    gt   value 3      key4    gt   value 4      key5    gt   value 5        to remove   array  key2    key4      result   array diff key  my array  array flip  to remove     print r  result     Output   Array    key1    gt  value 1  key3    gt  value 3  key5    gt  value 5

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if you want to remove a specific object of an array by reference of that object you can do following   unset  array array search  object  array       Example    lt  php class Foo       public  id      public  name      foo1   new Foo     foo1- gt id   1   foo1- gt name    Name1     foo2   new Foo     foo2- gt id   2   foo2- gt name    Name2     foo3   new Foo     foo3- gt id   3   foo3- gt name    Name3      array   array  foo1  foo2  foo3   unset  array array search  foo2  array      echo   lt pre gt    var dump  array   echo   lt  pre gt      gt    Result   array 2     0   gt      object Foo  1  2              id    gt          int 1            name    gt          string 5   Name1         2   gt      object Foo  3  2              id    gt          int 3            name    gt          string 5   Name3            Note that if the object occures several times it will only be removed the first occurence

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If you have a numerically indexed array where all values are unique  or they are non-unique but you wish to remove all instances of a particular value   you can simply use array diff   to remove a matching element  like this    my array   array diff  my array  array  Value to remove       For example    my array   array  Andy    Bertha    Charles    Diana    echo sizeof  my array      n    my array   array diff  my array  array  Charles     echo sizeof  my array     This displays the following   4 3   In this example  the element with the value  Charles  is removed as can be verified by the sizeof   calls that report a size of 4 for the initial array  and 3 after the removal

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If you have to delete multiple values in an array and the entries in that array are objects or structured data   array filter  1  is your best bet  Those entries that return a true from the callback function will be retained     array           x   gt 1  y   gt 2  z   gt 3          x   gt 2  y   gt 4  z   gt 6          x   gt 3  y   gt 6  z   gt 9       results   array filter  array  function  value        return  value  x    gt  2           gt     x   gt 3  y   gt 6 z  gt  9

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For associative arrays  with non-integer keys   Simply  unset  array  key   would work   For arrays having integer keys and if you want to maintain your keys     array      mango    red    orange    grapes     unset  array 2     array   array values  array    array splice  array  2  1

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To avoid doing a search one can play around with array diff    array   array 3  9  11  20    array   array diff  array  array 11        removes 11   In this case one doesn t have to search use the key

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Our initial array    arr   array  blue    green    red    yellow    green    orange    yellow    indigo    red      print r  arr         Remove the elements who s values are yellow or red    arr   array diff  arr  array  yellow    red       print r  arr     This is the output from the code above   Array        0    gt  blue      1    gt  green      2    gt  red      3    gt  yellow      4    gt  green      5    gt  orange      6    gt  yellow      7    gt  indigo      8    gt  red    Array        0    gt  blue      1    gt  green      4    gt  green      5    gt  orange      7    gt  indigo     Now  array values   will reindex a numerical array nicely  but it will remove all key strings from the array and replace them with numbers  If you need to preserve the key names  strings   or reindex the array if all keys are numerical  use array merge      arr   array merge array diff  arr  array  yellow    red      print r  arr     Outputs  Array        0    gt  blue      1    gt  green      2    gt  green      3    gt  orange      4    gt  indigo

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Solutions    To delete one element  use unset       unset  array 3    unset  array  foo         To delete multiple noncontiguous elements  also use unset       unset  array 3    array 5    unset  array  foo     array  bar         To delete multiple contiguous elements  use array splice       array splice  array   offset   length      Further explanation   Using these functions removes all references to these elements from PHP  If you want to keep a key in the array  but with an empty value  assign the empty string to the element    array 3     array  foo           Besides syntax  there s a logical difference between using unset   and assigning    to the element  The first says This doesn t exist anymore  while the second says This still exists  but its value is the empty string   If you re dealing with numbers  assigning 0 may be a better alternative  So  if a company stopped production of the model XL1000 sprocket  it would update its inventory with   unset  products  XL1000       However  if it temporarily ran out of XL1000 sprockets  but was planning to receive a new shipment from the plant later this week  this is better    products  XL1000     0    If you unset   an element  PHP adjusts the array so that looping still works correctly  It doesn t compact the array to fill in the missing holes  This is what we mean when we say that all arrays are associative  even when they appear to be numeric  Here s an example      Create a  numeric  array  animals   array  ant    bee    cat    dog    elk    fox    print  animals 1       Prints  bee  print  animals 2       Prints  cat  count  animals         Returns 6     unset   unset  animals 1       Removes element  animals 1     bee  print  animals 1       Prints    and throws an E NOTICE error print  animals 2       Still prints  cat  count  animals         Returns 5  even though  array 5  is  fox      Add a new element  animals       gnu      Add a new element  not Unix  print  animals 1       Prints     still empty print  animals 6       Prints  gnu   this is where  gnu  ended up count  animals         Returns 6     Assign     animals 2             Zero out value print  animals 2       Prints    count  animals         Returns 6  count does not decrease   To compact the array into a densely filled numeric array  use array values      animals   array values  animals     Alternatively  array splice   automatically reindexes arrays to avoid leaving holes      Create a  numeric  array  animals   array  ant    bee    cat    dog    elk    fox    array splice  animals  2  2   print r  animals   Array        0    gt  ant      1    gt  bee      2    gt  elk      3    gt  fox     This is useful if you re using the array as a queue and want to remove items from the queue while still allowing random access  To safely remove the first or last element from an array  use array shift   and array pop    respectively

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You can use the array pop method to remove the last element of an array    lt  php      a   array  one    two    Three        array pop  a       print r  a     gt  The out put will be Array    0    gt  one 1    gt  two    which deletes only last element of an array LIFO operation

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This may help      lt  php      a1   array  a   gt  red    b   gt  green    c   gt  blue    d   gt  yellow         a2   array  a   gt  purple    b   gt  orange        array splice  a1  0  2   a2       print r  a1     gt    The result will be   Array    0    gt  purple  1    gt  orange  c    gt  blue  d    gt  yellow

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x   array 1  2  3  4  5   var dump  x   unset  x 3       Here is the key to be deleted echo   lt br gt    array values  x   var dump  x

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There are two methods to do this task  unset   and array splice    Let us assume two arrays    array 1   array  a   gt  One    b   gt  Two    c   gt  Three      array 2   array  Red    Yellow    White    Black    Green      With unset    syntax - unset array element   unset  array 1  a        Any valid key unset  array 2 0       Any valid index    after removing an array element  the array index does not change   With array splice    syntax - array splice array  index  length   array splice  array 1  1  1      Remove one element from  array 1 from index 1 array splice  array 2  3  1      Remove one element from  array 2 from index 3    All array elements are reindexed after removing an element from the array

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There are different ways to delete an array element  where some are more useful for some specific tasks than others  Deleting a single array element If you want to delete just one array element you can use unset   or alternatively  array splice    If you know the value and don   t know the key to delete the element you can use  array search   to get the key  This only works if the element does not occur more than once  since  array search returns the first hit only  unset   Note that when you use unset   the array keys won   t change  If you want to reindex the keys you can use  array values   after unset    which will convert all keys to numerically enumerated keys starting from 0  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot    unset  array 1                   Key which you want to delete  Output         0    gt  a      2    gt  c     array splice   method If you use  array splice   the keys will automatically be reindexed  but the associative keys won   t change     as opposed to  array values    which will convert all keys to numerical keys   array splice   needs the offset  not the key  as the second parameter  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot     array splice  array  1  1                           Offset which you want to delete  Output         0    gt  a      1    gt  c    array splice    same as unset    take the array by reference  You don   t assign the return values of those functions back to the array  Deleting multiple array elements If you want to delete multiple array elements and don   t want to call unset   or  array splice   multiple times you can use the functions  array diff   or  array diff key   depending on whether you know the values or the keys of the elements which you want to delete   array diff   method If you know the values of the array elements which you want to delete  then you can use  array diff    As before with unset   it won   t change the keys of the array  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot   3   gt   quot c quot     array    array diff  array    quot a quot    quot c quot                                   --------                               Array values which you want to delete  Output         1    gt  b     array diff key   method If you know the keys of the elements which you want to delete  then you want to use  array diff key    You have to make sure you pass the keys as keys in the second parameter and not as values  Keys won   t reindex  Code   array    0   gt   quot a quot   1   gt   quot b quot   2   gt   quot c quot     array    array diff key  array   0   gt   quot xy quot    quot 2 quot    gt   quot xy quot                                                                                       Array keys which you want to delete  Output         1    gt  b    If you want to use unset   or  array splice   to delete multiple elements with the same value you can use  array keys   to get all the keys for a specific value and then delete all elements

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There are two methods to do this task  unset   and array splice    Let us assume two arrays    array 1   array  a   gt  One    b   gt  Two    c   gt  Three      array 2   array  Red    Yellow    White    Black    Green      With unset    syntax - unset array element   unset  array 1  a        Any valid key unset  array 2 0       Any valid index    after removing an array element  the array index does not change   With array splice    syntax - array splice array  index  length   array splice  array 1  1  1      Remove one element from  array 1 from index 1 array splice  array 2  3  1      Remove one element from  array 2 from index 3    All array elements are reindexed after removing an element from the array

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unset   multiple  fragmented elements from an array  While unset   has been mentioned here several times  it has yet to be mentioned that unset   accepts multiple variables making it easy to delete multiple  noncontiguous elements from an array in one operation      Delete multiple  noncontiguous elements from an array  array      foo    bar    baz    quz     unset   array 2    array 3     print r  array      Output     foo    bar      unset   dynamically  unset   does not accept an array of keys to remove  so the code below will fail  it would have made it slightly easier to use unset   dynamically though     array   range 0 5    remove    1 2    array   unset   remove       FAILS   unexpected  unset   print r  array     Instead  unset   can be used dynamically in a foreach loop    array   range 0 5    remove    1 2   foreach   remove as  k  gt  v        unset  array  v      print r  array      Output    0  3  4  5     Remove array keys by copying the array  There is also another practice that has yet to be mentioned  Sometimes  the simplest way to get rid of certain array keys is to simply copy  array1 into  array2    array1   range 1 10   foreach   array1 as  v           Remove all even integers from the array     if   v   2              array2      v          print r  array2      Output    1  3  5  7  9      Obviously  the same practice applies to text strings    array1      foo     bar    baz     foreach   array1 as  v           Remove all strings beginning with underscore     if  strpos  v        false              array2      v          print r  array2      Output     foo    baz

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lt  php        If you want to remove a particular array element use this method      my array   array  key1   gt  value 1    key2   gt  value 2    key3   gt  value 3         print r  my array       if  array key exists  key1    my array             unset  my array  key1             print r  my array             else           echo  Key does not exist           gt    lt  php       To remove first array element      my array   array  key1   gt  value 1    key2   gt  value 2    key3   gt  value 3        print r  my array        new array   array slice  my array  1       print r  new array     gt     lt  php     echo   lt br  gt               To remove first array element to length        starts from first and remove two element      my array   array  key1   gt  value 1    key2   gt  value 2    key3   gt  value 3        print r  my array        new array   array slice  my array  1  2       print r  new array     gt         Output   Array    key1    gt  value 1  key2    gt  value 2  key3    gt   value 3   Array       key2    gt  value 2  key3    gt  value 3    Array    key1    gt  value 1  key2    gt  value 2  key3    gt  value 3    Array    key2    gt  value 2  key3    gt  value 3    Array    key1    gt  value 1  key2    gt  value 2  key3    gt  value 3    Array    key2    gt  value 2  key3    gt  value 3

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arrayName   array   1    gt   somevalue                        2    gt   somevalue1                        3    gt   somevalue3                         print r  arrayName 1       somevalue unset  arrayName 1     print r  arrayName

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Follow the default functions   PHP  unset  unset   destroys the specified variables  For more info  you can refer to PHP unset  Array   array  quot test1 quot    quot test2 quot    quot test3 quot    quot test3 quot     unset  Array 2      PHP  array pop  The array pop   function deletes the last element of an array  For more info  you can refer to PHP array pop  Array   array  quot test1 quot    quot test2 quot    quot test3 quot    quot test3 quot     array pop  Array     PHP  array splice  The array splice   function removes selected elements from an array and replaces it with new elements  For more info  you can refer to PHP array splice  Array   array  quot test1 quot    quot test2 quot    quot test3 quot    quot test3 quot     array splice  Array 1 2     PHP  array shift  The array shift   function removes the first element from an array  For more info  you can refer to PHP array shift  Array   array  quot test1 quot    quot test2 quot    quot test3 quot    quot test3 quot     array shift  Array

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For associative arrays  with non-integer keys   Simply  unset  array  key   would work   For arrays having integer keys and if you want to maintain your keys     array      mango    red    orange    grapes     unset  array 2     array   array values  array    array splice  array  2  1

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unset   destroys the specified variables   The behavior of unset   inside of a function can vary depending on what type of variable you are attempting to destroy   If a globalized variable is unset   inside of a function  only the local variable is destroyed  The variable in the calling environment will retain the same value as before unset   was called    lt  php     function destroy foo                 global  foo          unset  foo               foo    bar       destroy foo        echo  foo    gt    The answer of the above code will be bar   To unset   a global variable inside of a function    lt  php     function foo                 unset  GLOBALS  bar                 bar    something       foo      gt

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unset  array  index

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This may help      lt  php      a1   array  a   gt  red    b   gt  green    c   gt  blue    d   gt  yellow         a2   array  a   gt  purple    b   gt  orange        array splice  a1  0  2   a2       print r  a1     gt    The result will be   Array    0    gt  purple  1    gt  orange  c    gt  blue  d    gt  yellow

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unset doesn t change the index  but array splice does    arrayName   array  1    gt   somevalue                       2    gt   somevalue1                       3    gt   somevalue3                      500   gt   somevalue500                              echo  arrayName  500          somevalue500     array splice  arrayName  1  2        print r  arrayName         Array    0    gt  somevalue  1    gt  somevalue500          arrayName   array   1    gt   somevalue                            2    gt   somevalue1                            3    gt   somevalue3                           500   gt   somevalue500                                  echo  arrayName  500          somevalue500     unset  arrayName 1         print r  arrayName         Array    0    gt  somevalue  1    gt  somevalue500

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Follow the default functions   PHP  unset  unset   destroys the specified variables  For more info  you can refer to PHP unset  Array   array  quot test1 quot    quot test2 quot    quot test3 quot    quot test3 quot     unset  Array 2      PHP  array pop  The array pop   function deletes the last element of an array  For more info  you can refer to PHP array pop  Array   array  quot test1 quot    quot test2 quot    quot test3 quot    quot test3 quot     array pop  Array     PHP  array splice  The array splice   function removes selected elements from an array and replaces it with new elements  For more info  you can refer to PHP array splice  Array   array  quot test1 quot    quot test2 quot    quot test3 quot    quot test3 quot     array splice  Array 1 2     PHP  array shift  The array shift   function removes the first element from an array  For more info  you can refer to PHP array shift  Array   array  quot test1 quot    quot test2 quot    quot test3 quot    quot test3 quot     array shift  Array

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lt  php      array   array  your array         array   array diff  array    element you want to delete       gt    Create your array in the variable  array and then where I have put  element you want to delete  you put something like   a   And if you want to delete multiple items then   a    b

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Our initial array    arr   array  blue    green    red    yellow    green    orange    yellow    indigo    red      print r  arr         Remove the elements who s values are yellow or red    arr   array diff  arr  array  yellow    red       print r  arr     This is the output from the code above   Array        0    gt  blue      1    gt  green      2    gt  red      3    gt  yellow      4    gt  green      5    gt  orange      6    gt  yellow      7    gt  indigo      8    gt  red    Array        0    gt  blue      1    gt  green      4    gt  green      5    gt  orange      7    gt  indigo     Now  array values   will reindex a numerical array nicely  but it will remove all key strings from the array and replace them with numbers  If you need to preserve the key names  strings   or reindex the array if all keys are numerical  use array merge      arr   array merge array diff  arr  array  yellow    red      print r  arr     Outputs  Array        0    gt  blue      1    gt  green      2    gt  green      3    gt  orange      4    gt  indigo

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If you have a numerically indexed array where all values are unique  or they are non-unique but you wish to remove all instances of a particular value   you can simply use array diff   to remove a matching element  like this    my array   array diff  my array  array  Value to remove       For example    my array   array  Andy    Bertha    Charles    Diana    echo sizeof  my array      n    my array   array diff  my array  array  Charles     echo sizeof  my array     This displays the following   4 3   In this example  the element with the value  Charles  is removed as can be verified by the sizeof   calls that report a size of 4 for the initial array  and 3 after the removal

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Destroy a single element of an array  unset     array1   array  A    B    C    D    E    unset  array1 2       Delete known index 2  value from array var dump  array1     The output will be   array 4       0   gt    string 1   A     1   gt    string 1   B     3   gt    string 1   D     4   gt    string 1   E      If you need to re index the array    array1   array values  array1   var dump  array1     Then the output will be   array 4       0   gt    string 1   A     1   gt    string 1   B     2   gt    string 1   D     3   gt    string 1   E      Pop the element off the end of array - return the value of the removed element  mixed array pop array  amp  array    stack   array  orange    banana    apple    raspberry     last fruit   array pop  stack   print r  stack   print r  Last Fruit    last fruit      Last element of the array   The output will be  Array        0    gt  orange      1    gt  banana      2    gt  apple   Last Fruit  raspberry   Remove the first element  red  from an array  - return the value of the removed element  mixed array shift   array  amp  array     color   array  a    gt   red    b    gt   green     c    gt   blue     first color   array shift  color   print r   color   print r   First Color     first color     The output will be   Array        b    gt  green      c    gt  blue   First Color  red

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You can simply use unset   to delete an array   Remember that an array must be unset after the foreach function

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Remove by value function removeFromArr  arr   val        unset  arr array search  val   arr         return array values  arr

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I d just like to say I had a particular object that had variable attributes  it was basically mapping a table and I was changing the columns in the table  so the attributes in the object  reflecting the table would vary as well    class obj       protected  fields   array  field1   field2        protected  field1   array        protected  field2   array        protected loadfields            This will load the  field1 and  field2 with rows of data for the column they describe     protected function clearFields  num           foreach  fields as  field                unset  this- gt  field  num                   This did not work the line below worked             unset  this- gt   field   num       You have to resolve  field first using                        The whole purpose of  fields was just  so I don t have to look everywhere in the code when they re changed  I just look at the beginning of the class and change the list of attributes and the  fields array content to reflect the new attributes

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unset   destroys the specified variables   The behavior of unset   inside of a function can vary depending on what type of variable you are attempting to destroy   If a globalized variable is unset   inside of a function  only the local variable is destroyed  The variable in the calling environment will retain the same value as before unset   was called    lt  php     function destroy foo                 global  foo          unset  foo               foo    bar       destroy foo        echo  foo    gt    The answer of the above code will be bar   To unset   a global variable inside of a function    lt  php     function foo                 unset  GLOBALS  bar                 bar    something       foo      gt

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I came here because I wanted to see if there was a more elegant solution to this problem than using unset  arr  i     To my disappointment these answers are either wrong or do not cover every edge case  Here is why array diff   does not work   Keys are unique in the array  while elements are not always unique   arr    1 2 2 3    foreach  arr as  i   gt   n        b   array diff  arr   n        echo  quot  n quot  json encode  b      Results     2 2 3   1 3   1 2 2    If two elements are the same they will be remove   This also applies for array search   and array flip    I saw a lot of answers with array slice   and array splice    but these functions only work with numeric arrays   All the answers I am aware if here does not answer the question  and so here is a solution that will work   arr    1 2 3    foreach  arr as  i   gt   n        b   array merge array slice  arr 0  i  array slice  arr  i 1        echo  quot  n quot  json encode  b      Results      2 3    1 3    1 2    Since unset  arr  i   will work on both associative array and numeric arrays this still does not answer the question  This solution is to compare the keys and with a tool that will handle both numeric and associative arrays  I use array diff uassoc   for this   This function compares the keys in a call back function   arr    1 2 2 3      arr     a   gt  z   b   gt  y   c   gt  x   d   gt  w    foreach  arr as  key   gt   n        b   array diff uassoc  arr    key  gt  n   function  a  b            if  a     b               return 1                        echo  quot  n quot  json encode  b          Results       2 2 3    1 2 3    1 2 2      b   gt  y   c   gt  x   d   gt  w      a   gt  z   c   gt  x   d   gt  w      a   gt  z   b   gt  y   d   gt  w      a   gt  z   b   gt  y   c   gt  x

User · Answer

Suppose you have the following array   Array        user id    gt  193      storage    gt  5     To delete storage  do   unset  attributes  storage      attributes   array filter  attributes     And you get   Array        user id    gt  193

User · Answer

Remove by value function removeFromArr  arr   val        unset  arr array search  val   arr         return array values  arr

[php] Deleting an element from an array in PHP

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