Assign value from one associative array of php into another array

Question

I have a variable $params which gets data from the database:

$params = mssql_fetch_array($result)

As far as I know, it is associative array. I want another array $tempParams to hold the value of this array. Can I assign it by using the following statement:

$tempParams = $params

In addition, do I need one single statement to declare and assign a value to $tempParams, or can these be separated?

One more question I would like to ask is that following statement is correct; While $tempParams contains values;

$params['column1'] = $tempParams['newColumns']

Answer 1

Yes you can, but that could cause some kind of aliasing if you're dealing with Objects (depending on which PHP version you're using).

Why is it that you want to copy the array? Can't you work with the same original variable ($params)?

Answer 2

Yes,

$tempParams = $params;

Will copy all values from $params to $tempParams.

$params['foo'] = 'bar';
echo $tempParams['foo']; //nothing
$tempParams = $params;
echo $tempParams['foo']; //'bar'
$params['foo'] = 'hai';
echo $tempParams['foo']; //still: 'bar'

Answer 3

As far as whether or not your array is associative, read the documentation on mysql_fetch_array()

As far as assignment goes, you actually can put it in one statement

$tempParams = $params = mysql_fetch_array( $result, MYSQL_ASSOC );

This simple test shows that when you do an assignment like this, both variables are separate copies and not references.

$a = $b = array( 1, 2, 3 );

$b[1] = 'x';

echo '<pre>';
print_r( $a );
print_r( $b );
echo '</pre>';

Answer 4

Yes, the = operator will copy the array exactly.

You can check yourself:

// get the $params from DB
print_r ($params); // will output array contents
$tempParams = $params;
print_r ($tempParams); // must be the same as above

There’s no such thing as “declaring” variables in PHP, but if you wish to say that $tempParams is an array somewhere before assigning, you can do it like this:

$tempParams = array ();

This will make $tempParams an array with no elements inside.

Answer 5

For arrays, numeric and associative, the = operator will make a copy of the variable. And both variables are completely independent of one another. However, when dealing with objects, the = operator creates a reference to the object, and both variables point to the exact same object.