Best way to initialize empty array in PHP

Question

In certain other languages  AS3 for example   it has been noted that initializing a new array is faster if done like this var foo      rather than var foo   new Array   for reasons of object creation and instantiation  I wonder whether there are any equivalences in PHP   class Foo       private  arr   array       is there another   better way

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In PHP an array is an array  there is no primitive vs  object consideration  so there is no comparable optimization to be had

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Initializing a simple array     lt  php  array1 array 10 20 30 40 50     gt    Initializing array within array     lt  php   array2 array 6  santosh   rahul  array  x   y   z       gt    Source   Sorce for the code

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In ECMAScript implementations  for instance  ActionScript or JavaScript   Array   is a constructor function and    is part of the array literal grammar  Both are optimized and executed in completely different ways  with the literal grammar not being dogged by the overhead of calling a function   PHP  on the other hand  has language constructs that may look like functions but aren t treated as such  Even with PHP 5 4  which supports    as an alternative  there is no difference in overhead because  as far as the compiler parser is concerned  they are completely synonymous      Before 5 4  you could only write  array   array       foo    gt   bar        bar    gt   foo          As of PHP 5 4  the following is synonymous with the above  array          foo    gt   bar        bar    gt   foo        If you need to support older versions of PHP  use the former syntax  There s also an argument for readability but  being a long-time JS developer  the latter seems rather natural to me   I actually made the mistake of trying to initialise arrays using    when I was first learning PHP   This change to the language was originally proposed and rejected due to a majority vote against by core developers with the following reason      This patch will not be accepted because slight majority of the core developers voted against  Though if you take a accumulated mean between core developers and userland votes seems to show the opposite it would be irresponsible to submit a patch witch is not supported or maintained in the long run    However  it appears there was a change of heart leading up to 5 4  perhaps influenced by the implementations of support for popular databases like MongoDB  which use ECMAScript syntax

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Prior to PHP 5 4    myArray   array      PHP 5 4 and higher   myArray

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myArray          Creates empty array   You can push values onto the array later  like so    myArray      tree    myArray      house    myArray      dog     At this point   myArray contains  tree    house  and  dog   Each of the above commands appends to the array  preserving the items that were already there   Having come from other languages  this way of appending to an array seemed strange to me  I expected to have to do something like  myArray     dog  or something    or maybe an  add    method like Visual Basic collections have  But this direct append syntax certainly is short and convenient   You actually have to use the unset   function to remove items   unset  myArray 1           would remove  house  from the array  arrays are zero-based    unset  myArray          would destroy the entire array   To be clear  the empty square brackets syntax for appending to an array is simply a way of telling PHP to assign the indexes to each value automatically  rather than YOU assigning the indexes  Under the covers  PHP is actually doing this    myArray 0     tree    myArray 1     house    myArray 2     dog     You can assign indexes yourself if you want  and you can use any numbers you want  You can also assign index numbers to some items and not others  If you do that  PHP will fill in the missing index numbers  incrementing from the largest index number assigned as it goes   So if you do this    myArray 10     tree    myArray 20     house    myArray      dog         the item  dog  will be given an index number of 21  PHP does not do intelligent pattern matching for incremental index assignment  so it won t know that you might have wanted it to assign an index of 30 to  dog   You can use other functions to specify the increment pattern for an array  I won t go into that here  but its all in the PHP docs   Cheers   - Cameron

User · Answer

Try this        arr    array  null      var dump  arr           will print        array 0

User · Answer

There is no other way  so this is the best   Edit  This answer is not valid since PHP 5 4 and higher

User · Answer

What you re doing is 100  correct   In terms of nice naming it s often done that private protected properties are preceded with an underscore to make it obvious that they re not public  E g  private   arr   array   or public  arr   array

[php] Best way to initialize (empty) array in PHP

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