PHP append one array to another not array push or

Question

How to append one array to another without comparing their keys    a   array   a    b      b   array   c    d       At the end it should be  Array   0   gt a  1   gt b  2   gt c  3   gt d   If I use something like    or array push  it will cause one of these results   Array   0   gt a  1   gt b  2   gt Array   0   gt c  1   gt d       or Array   0   gt c  1   gt d     It just should be something  doing this  but in a more elegant way   foreach    b AS  var        a      var

User · Accepted Answer

array merge is the elegant way    a   array  a    b     b   array  c    d     merge   array merge  a   b        merge is now equals to array  a   b   c   d      Doing something like    merge    a    b      merge now equals array  a   b     Will not work  because the   operator does not actually merge them  If they  a has the same keys as  b  it won t do anything

User · Answer

It s a pretty old post  but I want to add something about appending one array to another   If   one or both arrays have associative keys the keys of both arrays don t matter   you can use array functions like this   array merge array values  array   array values  appendArray      array merge doesn t merge numeric keys so it appends all values of  appendArray  While using native php functions instead of a foreach-loop  it should be faster on arrays with a lot of elements   Addition 2019-12-13  Since PHP 7 4  there is the possibility to append or prepend arrays the Array Spread Operator way        a    3  4        b    1  2      a     As before  keys can be an issue with this new feature        a     a    gt  3   b    gt  4        b     c    gt  1   a    gt  2      a      Fatal error  Uncaught Error  Cannot unpack array with string keys        a    3   gt  3  4   gt  4        b    1   gt  1  4   gt  2      a     array 4       1      int 1     4      int 2     5      int 3     6      int 4          a    1   gt  1  2   gt  2        b        a  3   gt  3  1   gt  4     array 3       0      int 1     1      int 4     3      int 3

User · Answer

if you want to merge empty array with existing new value  You must initialize it first    products   array      just example for  brand id 1  brand id lt  3  brand id       array merge  products getByBrand  brand id         it will create empty array print r  a      check if array of products is empty for  brand id 1  brand id lt  3  brand id       if empty  products         products   getByBrand  brand id      else      array merge  products getByBrand  brand id             it will create array of products   Hope its help

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Before PHP7 you can use   array splice  a  count  a   0   b     array splice   operates with reference to array  1st argument  and puts array  4th argument  values in place of list of values started from 2nd argument and number of 3rd argument  When we set 2nd argument as end of source array and 3rd as zero we append 4th argument values to 1st argument

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Another way to do this in PHP 5 6  would be to use the     token   a   array  a    b     b   array  c    d     array push  a      b        a is now equals to array  a   b   c   d      This will also work with any Traversable   a   array  a    b     b   new ArrayIterator array  c    d      array push  a      b        a is now equals to array  a   b   c   d      A warning though    in PHP versions before 7 3 this will cause a fatal error if  b is an empty array or not traversable e g  not an array in PHP 7 3 a warning will be raised if  b is not traversable

User · Answer

How about this    appended    a    b

User · Answer

Following on from answer s by bstoney and Snark I did some tests on the various methods      Test 1  array merge   array1    array2   array fill 0  50000   aa     start   microtime true    array1   array merge  array1   array2   echo sprintf  Test 1    06f n   microtime true  -  start       Test2  foreach   array1    array2   array fill 0  50000   aa     start   microtime true   foreach   array2 as  v         array1      v    echo sprintf  Test 2    06f n   microtime true  -  start       Test 3      token     PHP 5 6  and produces error if  array2 is empty  array1    array2   array fill 0  50000   aa     start   microtime true   array push  array1      array2   echo sprintf  Test 3    06f n   microtime true  -  start     Which produces   Test 1  0 002717  Test 2  0 006922  Test 3  0 004744   ORIGINAL  I believe as of PHP 7  method 3 is a significantly better alternative due to the way foreach loops now act  which is to make a copy of the array being iterated over   Whilst method 3 isn t strictly an answer to the criteria of  not array push  in the question  it is one line and the most high performance in all respects  I think the question was asked before the     syntax was an option   UPDATE 25 03 2020  I ve updated the test which was flawed as the variables weren t reset  Interestingly  or confusingly  the results now show as test 1 being the fastest  where it was the slowest  having gone from 0 008392 to 0 002717  This can only be down to PHP updates  as this wouldn t have been affected by the testing flaw   So  the saga continues  I will start using array merge from now on

User · Answer

lt  php    Example 1  Merging associative arrays  When two or more arrays have same key    then the last array key value overrides the others one    array1   array  a    gt   JAVA    b    gt   ASP     array2   array  c    gt   C    b    gt   PHP    echo    lt br gt  Example 1 Output   lt br gt    print r array merge  array1  array2        Example 2  When you want to merge arrays having integer keys and   want to reset integer keys to start from 0 then use array merge   function    array3  array 5   gt   CSS  6   gt   CSS3     array4  array 8   gt   JAVASCRIPT  9   gt   HTML    echo    lt br gt  Example 2 Output   lt br gt    print r array merge  array3  array4        Example 3  When you want to merge arrays having integer keys and    want to retain integer keys as it is then use PLUS     operator to merge arrays    array5  array 5   gt   CSS  6   gt   CSS3     array6  array 8   gt   JAVASCRIPT  9   gt   HTML    echo    lt br gt  Example 3 Output   lt br gt    print r  array5  array6       Example 4  When single array pass to array merge having integer keys    then the array return by array merge have integer keys starting from 0    array7  array 3   gt   CSS  4   gt   CSS3    echo    lt br gt  Example 4 Output   lt br gt    print r array merge  array7      gt    Output   Example 1 Output  Array    a    gt  JAVA  b    gt  PHP  c    gt  C    Example 2 Output  Array    0    gt  CSS  1    gt  CSS3  2    gt  JAVASCRIPT  3    gt  HTML    Example 3 Output  Array    5    gt  CSS  6    gt  CSS3  8    gt  JAVASCRIPT  9    gt  HTML    Example 4 Output  Array    0    gt  CSS  1    gt  CSS3     Reference Source Code

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Since PHP 7 4 you can use the     operator  This is also known as the splat operator in other languages  including Ruby     parts     apple    pear     fruits     banana    orange       parts   watermelon    var dump  fruits     Output  array 5         0   gt      string 6   banana       1   gt      string 6   orange       2   gt      string 5   apple       3   gt      string 4   pear       4   gt      string 10   watermelon      Splat operator should have better performance than array merge  That   s not only because the splat operator is a language structure while array merge is a function  but also because compile time optimization can be performant for constant arrays   Moreover  we can use the splat operator syntax everywhere in the array  as normal elements can be added before or after the splat operator    arr1    1  2  3    arr2    4  5  6    arr3        arr1      arr2    arr4        arr1      arr3  7  8  9

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For big array  is better to concatenate without array merge  for avoid a memory copy    array1   array fill 0 50000  aa     array2   array fill 0 100  bb        Test 1  array merge   start   microtime true    r1   array merge  array1   array2   echo sprintf  Test 1    06f n   microtime true  -  start       Test2  avoid copy   start   microtime true   foreach   array2 as  v         array1      v    echo sprintf  Test 2    06f n   microtime true  -  start        Test 1  0 004963    Test 2  0 000038

User · Answer

Why not use   appended   array merge  a  b      Why don t you want to use this  the correct  built-in method

User · Answer

foreach loop is faster than array merge to append values to an existing array  so choose the loop instead if you want to add an array to the end of another      Create an array of arrays  chars       for   i   0   i  lt  15000   i           chars     array fill 0  10   a          test array merge  new        start   microtime TRUE   foreach   chars as  splitArray         new   array merge  new   splitArray     echo microtime true  -  start       gt  14 61776 sec     test foreach  new        start   microtime TRUE   foreach   chars as  splitArray        foreach   splitArray as  value             new      value          echo microtime true  -  start       gt  0 00900101 sec       gt  1600 times faster

[php] PHP append one array to another (not array_push or +)

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