Which Of These 3 Is An Empty Array ?

developer_web

Folks,

In your professional experience and opinion which of these are not empty arrays ?
Just experimenting. That is all.

$array_01a = array();
$array_02a = array('');
$array_03a = array("");
$array_04a = array(,);

$array_01b = array( );
$array_02b = array(' ');
$array_03b = array(" ");
$array_04b = array(  ,  );

$array_01c = array( '' );
$array_02c = array( "" );

$array_01d = array( ' ' );
$array_02d = array( " " );

$array_01e = array('','');
$array_02e = array("","");
$array_03e = array('',""); //Sngl & DBL Quotes

$array_01f = array(' ',' ');
$array_02f = array(" "," ");
$array_03f = array(' '," "); //Sngl & DBL Quotes

$array_01g = array( '','' );
$array_02g = array( "","" );
$array_03g = array( '',"" ); //Sngl & DBL Quotes

$array_01h = array('' , '');
$array_02h = array("" , "");
$array_03h = array('' , ""); //Sngl & DBL Quotes

$array_01i = array( '' , '' );
$array_02i = array( "" , "" );
$array_03i = array( '' , "" ); //Sngl & DBL Quotes

$array_01j = array( ' ',' ' );
$array_02j = array( " "," " );
$array_03j = array( ' '," " ); //Sngl & DBL Quotes

$array_01k = array(' ' , ' ');
$array_02k = array(" " , " ");
$array_03k = array(' ' , " "); //Sngl & DBL Quotes

$array_01l = array( ' ' , ' ' );
$array_02l = array( " " , " " );
$array_03l = array( ' ' , " " ); //Sngl & DBL Quotes

$array_1 = array(1);
$array_2 = array('1');
$array_3 = array("1");
$array_4 = array('1',"1"); //Sngl & DBL Quotes.

developer_web

Folks,

Q1.
How to findout if an array exists or not ?

Q2.
And, how to findout if an array is empty or not ?
Talking about non-key value arrays, like the ones shown above.

Q3.
I use the following 'Set A' codes to findout if array is empty of values or not. Are these codes ok or not ? If not then why not ?

Set A: 1

If($array)
{
    echo 'array full';
}

Set A: 2

If(!$array)
{
    echo 'array empty';
}

Set A: 3.

If(empty($array))
{
    echo 'array full';
}

Set A: 4.

If(!empty($array))
{
    echo 'array empty';
}

Set A: 5.

If(empty($array) == FALSE)
{
    echo 'array empty';
}

Set A: 6.

If(empty($array) == 'FALSE')
{
    echo 'array empty';
}

Set A: 7.

If(empty($array) == "FALSE")
{
    echo 'array empty';
}

I reckon all followings are wrong:
Notice the closing brackets and operator on each example.

Q4. Are all these wrong or not to findout if an array is empty of values or not ?

Set B: 1

If(empty($array == FALSE))
{
    echo 'array empty';
}

Set B: 2

If(empty($array == 'FALSE'))
{
    echo 'array empty';
}

Set B: 3

If(empty($array == "FALSE"))
{
    echo 'array empty';
}

Set B: 4

If(empty($array) = FALSE)
{
    echo 'array empty';
}

Set B: 5

If(empty($array) = 'FALSE')
{
    echo 'array empty';
}

Set B: 6

If(empty($array) = "FALSE")
{
    echo 'array empty';
}

Set B: 7

If(empty($array = FALSE))
{
    echo 'array empty';
}

Set B: 8

If(empty($array = 'FALSE'))
{
    echo 'array empty';
}

Set B: 9

If(empty($array = "FALSE")
{
    echo 'array empty';
}

Show me which ones you prefer over the others to findout if an array is empty or not.
Give your rankings to all the code samples I mentioned so I can see which method you prefer.

Thanks

NogDog

developer_web If(empty($array == "FALSE"))

This is just plain wrong.

The argument provided to empty() should be a variable, not a comparison; so it would be if(empty($array) == false), which can be simplified to if(!empty($array)) with the ! operator. (You can read that as "if not empty".)
When comparing to false or true, do not quote them, as then you are just comparing to a string, not a reserved word with a specific meaning in PHP.

developer_web

Folks,

Imagine no array exists like so:

$arr = array();

Imagine I either forgot to build the array or I got the array name wrong when checking if array is set with values or not and imagine I checked with these 3 codes if array got values or not.

if($arr="FALSE") // DBL quotes.
{
	echo '4. empty'; //This line echoes
}
else
{
	echo '4. full'; //This line doesn't echo
}

Q5a. Is above code ok to check if array is full or not ?
I did not create the array and I get echoed array is empty. Am I getting this echoed because the array is empty or am I getting this echoed because the variable is empty or the variable doesn't exist ? Which is it ?

if($arr='FALSE') // SNGL quotes.
{
	echo '4. empty'; //This line echoes
}
else
{
	echo '4. full'; //This line doesn't echo
}

Q5b. Is above code ok to check if array is full or not ?
I did not create the array and I get echoed array is empty. Am I getting this echoed because the array is empty or am I getting this echoed because the variable is empty or the variable doesn't exist ? Which is it ?

if($arr="FALSE") // DBL quotes.
{
	echo '4. empty'; //This line doesnt echoe
}
else
{
	echo '4. full'; //This line gets echoed
}

Q5c. Is above code ok to check if array is full or not ?
I did not create the array and I get echoed array is FULL. Why this false statement ?

When you answer all 3 questions do number your answers likewise or I might get confused to which question you are replying.

developer_web

NogDog

Everything you said makes sense.
However, I have seen others quoting TRUE/FALSE thus turning them into strings but my tests most of the time show the TRUE/FALSE string gets counted by php as Boolean and not string if I use the "==" before the "TRUE"/'FALSE' quoted string. Strange!
Nevermind. Sticking to your advice.

developer_web

Folks,

Lately been using is_array() to check if array exists or not.

Using array_key_exists() to check of first array value exists or not.

$arr1 = array(1,10);
if(ISSET($arr1))
{
	if($arr1 != '')
	{
		//Array has to exist to use array_key_exists(). Array Variable Name has to exist atleast even if it holds no values. Eg $arr.
		if(array_key_exists('0',$arr1))
		{	
			echo '3. $arr1[0] exists!';
		}
		else
		{
			echo '4. $arr1[0] doesn not exist!';
		}
	}
	else
	{
		echo '2. Array Values missing';
	}
}
else
{
	echo '1. Array missing';
}

$arr2 = array('0'=>'1','1'=>'5');
if(ISSET($arr2))
{
	if($arr2 != '')
	{
		//Array has to exist to use array_key_exists(). Array Variable Name has to exist atleast even if it holds no values. Eg $arr.
		if(array_key_exists('0',$arr2))
		{	
			echo '3. $arr2[0] exists!';
		}
		else
		{
			echo '4. $arr2[0] doesn not exist!';
		}
	}
	else
	{
		echo '2. Array Values missing';
	}
}
else
{
	echo '1. Array missing';
}