PHP merge two arrays while keeping keys instead of reindexing

Question

How can I merge two arrays  one with string    value pairs and another with int    value pairs  while keeping the string int keys  None of them will ever overlap  because one has only strings and the other has only integers    Here is my current code  which doesn t work  because array merge is re-indexing the array with integer keys       get all id vars by combining the static and dynamic  staticIdentifications   array   Users  userID   gt   USERID    Users  username   gt   USERNAME        get the dynamic vars  formatted  varID   gt  varName  companyVarIdentifications   CompanyVars  getIdentificationVarsFriendly   SESSION  companyID        merge the static and dynamic vars      BUT KEEP THE INT INDICES       idVars   array merge  staticIdentifications   companyVarIdentifications

User · Answer

While this question is quite old I just want to add another possibility of doing a merge while keeping keys.

Besides adding key/values to existing arrays using the + sign you could do an array_replace.

$a = array('foo' => 'bar', 'some' => 'string');
$b = array(42 => 'answer to the life and everything', 1337 => 'leet');

$merged = array_replace($a, $b);

The result will be:

Array
(
  [foo] => bar
  [some] => string
  [42] => answer to the life and everything
  [1337] => leet
)

Same keys will be overwritten by the latter array.
There is also an array_replace_recursive, which do this for subarrays, too.

Live example on 3v4l.org

User · Answer

Try array replace recursive or array replace functions   a   array  userID    gt  1   username   gt  2   array     userID   gt  1    username   gt  2    b   array  userID    gt  1   companyID    gt  3   array      userID    gt  1     companyID    gt  3    c   array replace recursive  a  b   array     userID   gt  1    username   gt  2    companyID   gt  3     http   php net manual en function array-replace-recursive php

User · Answer

You can simply  add  the arrays    gt  gt   a   array 1  2  3   array     0   gt  1    1   gt  2    2   gt  3     gt  gt   b   array  a    gt  1   b    gt  2   c    gt  3  array      a    gt  1     b    gt  2     c    gt  3     gt  gt   a    b array     0   gt  1    1   gt  2    2   gt  3     a    gt  1     b    gt  2     c    gt  3

User · Answer

Considering that you have    replaced   array  1    gt   value1    4    gt   value4     replacement   array  4    gt   value2    6    gt   value3      Doing  merge    replacement    replaced  will output   Array  4    gt   value2    6    gt   value3    1    gt   value1      The first array from sum will have values in the final output   Doing  merge    replaced    replacement  will output   Array  1    gt   value1    4    gt   value4    6    gt   value3

User · Answer

Two arrays can be easily added or union without chaning their original indexing by   operator  This will be very help full in laravel and codeigniter select dropdown          empty option   array               gt  Select Option                  option list   array            1  gt  Red             2  gt  White             3  gt  Green                   arr option    empty option    option list    Output will be     arr option   array         gt  Select Option     1  gt  Red      2  gt  White      3  gt  Green

User · Answer

Hello year 2010 question  The OP  s requirement is preserve keys  keep keys  and not overlap  I think overwrite   In some case such as numeric keys it is possible but if string keys it seems to be not possible  If you use array merge   the numeric keys will always re-index or renumbered  If you use array replace    array replace recursive   it will be overlap or overwrite from the right to the left  The value with the same key on first array will be replaced with second array  If you use  array1    array2 as the comment was mentioned  if the keys are same then it will keep the value from first array but drop the second array  Custom function  Here is my function that I just wrote to work on the same requirements  You are free to use for any purpose         Array custom merge  Preserve indexed array key  numbers  but overwrite string key  same as PHP s  array merge    function          If the another array key is string  it will be overwrite the first array  lt br gt     If the another array key is integer  it will be add to first array depend on duplicated key or not      If it is not duplicate key with the first  the key will be preserve and add to the first array     If it is duplicated then it will be re-index the number append to the first array         param array  array1 The first array is main array      param array     arrays The another arrays to merge with the first      return array Return merged array      function arrayCustomMerge array  array1  array     arrays   array       foreach   arrays as  additionalArray            foreach   additionalArray as  key   gt   item                if  is string  key                        if associative array                     item on the right will always overwrite on the left                   array1  key     item                elseif  is int  key   amp  amp   array key exists  key   array1                        if key is number  this should be indexed array                     and if array 1 is not already has this key                     add this array with the key preserved to array 1                   array1  key     item                else                      if anything else                       get all keys from array 1  numbers only                    array1Keys   array filter array keys  array1    is int                       next key index   get max array key number   1                   nextKeyIndex    intval max  array1Keys     1                   unset  array1Keys                      set array with the next key index                   array1  nextKeyIndex     item                  unset  nextKeyIndex                             endforeach   additionalArray         unset  item   key           endforeach      unset  additionalArray        return  array1      arrayCustomMerge  Testing   lt  php  array1          cat         bear         fruitred    gt   apple       3 1   gt   dog       null   gt   null       array2         1   gt   polar bear       20   gt   monkey        fruitred    gt   strawberry        fruityellow    gt   banana       null   gt   another null          require  arrayCustomMerge    function here   function printDebug  message        echo   lt pre gt        print r  message       echo   lt  pre gt     PHP EOL     echo  array1   lt br gt    printDebug  array1   echo  array2   lt br gt    printDebug  array2     echo PHP EOL     lt hr gt     PHP EOL   PHP EOL    echo  arrayCustomMerge  lt br gt     merged   arrayCustomMerge  array1   array2   printDebug  merged     assert  merged 0      cat    array key 0 should be   cat      assert  merged 1      bear    array key 1 should be   bear      assert  merged  fruitred       strawberry    array key   fruitred   should be   strawberry      assert  merged 3      dog    array key 3 should be   dog      assert array search  another null    merged      false     another null   should be merged     assert array search  polar bear    merged      false     polar bear   should be merged     assert  merged 20      monkey    array key 20 should be   monkey      assert  merged  fruityellow       banana    array key   fruityellow   should be   banana       The results  array1   Array        0    gt  cat      1    gt  bear      fruitred    gt  apple      3    gt  dog          gt  null    array2   Array        1    gt  polar bear      20    gt  monkey      fruitred    gt  strawberry      fruityellow    gt  banana          gt  another null    --- arrayCustomMerge   Array        0    gt  cat      1    gt  bear      fruitred    gt  strawberry      3    gt  dog          gt  another null      4    gt  polar bear      20    gt  monkey      fruityellow    gt  banana

[php] PHP: merge two arrays while keeping keys instead of reindexing?

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