Can t concatenate 2 arrays in PHP

Question

I ve recently learned how to join 2 arrays using the   operator in PHP   But consider this code      array   array  Item 1      array    array  Item 2     var dump  array     Output is     array 1       0      string 6   Item   1      Why does this not work  Skipping the shorthand and using  array    array   array  Item 2   does not work either  Does it have something to do with the keys

User · Answer

IMO some of the previous answers are incorrect! (It's possible to sort the answers to start from oldest to newest).

array_merge() actually merges the arrays, meaning, if the arrays have a common item one of the copies will be omitted. Same goes for + (union).

I didn't find a "work-around" for this issue, but to do it manually...

Here it goes:

<?php
$part1 = array(1,2,3);
echo "array 1 = \n";
print_r($part1);
$part2 = array(4,5,6);
echo "array 2 = \n";
print_r($part2);
$ans = NULL;
for ($i = 0; $i < count($part1); $i++) {
    $ans[] = $part1[$i];
}
for ($i = 0; $i < count($part2); $i++) {
    $ans[] = $part2[$i];
}
echo "after arrays concatenation:\n";
print_r($ans);
?>

User · Answer

array   array  Item 1     array push  array  Item 2      or   array      Item 2

User · Answer

you may use operator     array3    array1  array2

User · Answer

Try saying    array     array  Item 2       Although it looks like you re trying to add an array into an array  thus  array     but that s not what your title suggests

User · Answer

Both will have a key of 0  and that method of combining the arrays will collapse duplicates  Try using array merge   instead    arr1   array  foo       Same as array 0   gt   foo    arr2   array  bar       Same as array 0   gt   bar       Will contain array  foo    bar     combined   array merge  arr1   arr2     If the elements in your array used different keys  the   operator would be more appropriate    arr1   array  one    gt   foo     arr2   array  two    gt   bar        Will contain array  one    gt   foo    two    gt   bar     combined    arr1    arr2    Edit  Added a code snippet to clarify

User · Answer

Use array merge   See the documentation here  http   php net manual en function array-merge php     Merges the elements of one or more arrays together so that the values of one are appended to the end of the previous one  It returns the resulting array

User · Answer

It is indeed a key conflict  When concatenating arrays  duplicate keys are not overwritten   Instead you must use array merge     array   array merge array  Item 1    array  Item 2

User · Answer

is called the Union operator  which differs from a Concatenation operator  PHP doesn t have one for arrays   The description clearly says      The   operator appends elements of remaining keys from the right handed array to the left handed  whereas duplicated keys are NOT overwritten    With the example    a   array  a    gt   apple    b    gt   banana     b   array  a    gt   pear    b    gt   strawberry    c    gt   cherry     c    a    b   array 3        a    gt    string 5   apple      b    gt    string 6   banana      c    gt    string 6   cherry      Since both your arrays have one entry with the key 0  the result is expected   To concatenate  use array merge

User · Answer

Try array merge    array1   array  Item 1      array2   array  Item 2      array3   array merge  array1   array2     I think its because you are not assigning a key to either  so they both have key of 0  and the   does not re-index  so its trying to over write it

User · Answer

This works for non-associative arrays   while   item   array shift  array2       null  amp  amp  array push  array1   item

[php] Can't concatenate 2 arrays in PHP

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