Should an array be declared before using it? [closed]

Answer 1

Best Practice is declaring it.

Reason: if for some reason someone turned on register_globals and $array is set before you use it, you can end up with strange results. If you declare it, you are always sure you have an empty array.

Answer 2

A Is better than B as @G-Nugget has said for the same reasons but the corollary is that it also makes your code harder to read if you have variables popping up out of nowhere.

Answer 3

IMO it depends on the complexity of your script. Just as it is with for example $i in foreach loops you might use array's a lot.

By defining the array first, you make sure that it is a new and empty array, which ensures that it contains no data from previous usage.

Answer 4

A is better. B will result in a PHP Notice when run, but will still work the same. As some other people mentioned and I overlooked initially, A will also make your code more robust by making sure that $array is what you want it to be when you need it and not some other variable type or previously defined variable.

Edit: the one time PHP doesn't throw a notice when using an undefined variable is when appending to an uninitialized array. From php.net:

E_NOTICE level error is issued in case of working with uninitialized variables, however not in the case of appending elements to the uninitialized array.

Answer 5

According to the manual, the part mentioning Creating/modifying with square bracket syntax, actually implies that creating arrays with $array[] = 'value'; is equally as right as creating arrays by declaring the variable as such before assigning values to it.

In other words, don't worry about it.

Answer 6

A is the better way but if its a known value I would do
$array=array('value');

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