PHP judgment Array is empty preferred method: Count ($arr), size ($arr);
Copy the Code code as follows:
$arr = Array ("");
echo count ($arr);
Echo size ($arr);
Output 1
Copy the Code code as follows:
$arr = Array ();
echo count ($arr);
Echo size ($arr);
Output 0
PHP judgment Array is empty method 2:empty ($arr);
Copy the Code code as follows:
$arr = Array ("");
$result = Empty ($arr);
$result = False
$arr = Array ();
$result = Empty ($arr);
$result = True
These two methods are sufficient to deal with the question of whether simple arrays and multidimensional arrays are empty, and individuals generally use empty () to make array non-null judgments, so that the sense code looks easier to understand.
Determine if the array is empty use this function just fine count if the output is 0 then the array is empty the following is a simple test code. PHP to determine if an array is empty code
Copy the Code code as follows:
<?php
$arr = Array ();
echo count ($arr);
?>
If the output is 0, the array is empty.
PHP judgment Array is empty method 2:empty ($arr);
Copy the Code code as follows:
$arr = Array ("");
$result = Empty ($arr);
$result = False
$arr = Array ();
$result = Empty ($arr);
$result = True
PHP judgment array is empty one, for loop
The simplest and most straightforward method is to iterate through the array with a for loop. The array of known dimensions can be judged, but what if it is an unknown multidimensional array?
PHP judgment array is empty two, implode ();
Use implode () to output the array as a string to determine if the output is empty. It seems like a good way to start at first, but as with a little bit more than two-dimensional arrays. As an example:
Copy the Code code as follows:
$arr = Array (array (), array (), arr (www.jb51.net) ay ());
$str = Implode (', ', $arr);
if (empty ($STR)) echo "null";
else echo "non-null";
It is obvious that $arr is a two-dimensional array with three empty arrays, which should also be empty, but the output is indeed non-empty. Judgment failed.
PHP judgment array is empty three, count ();
Copy the Code code as follows:
$arr = Array ("", "", "");
echo count ($arr);
PHP judgment array is empty four, In_array (", $arr));
Copy the Code code as follows:
$arr = Array ("D", "s", "");
Echo In_array (', $arr);
This can only indicate that there are empty elements in the array and cannot prove that the array is empty. It's not obvious.
PHP judgment Array is empty (five);
This Cpyeh thinks it's the same as the previous methods.
Copy the Code code as follows:
$arr = Array ("", "", "");
if (empty ($arr)) echo "null";
else echo "non-null";
The result is still non-empty
PHP judgment array is empty six, with strlen (), no content as if the length is 1
We can also add a sentence print_r ($arr) to the above example;
The above is to determine whether the PHP array is empty code, including the aspects of the content, I hope the PHP tutorial interested in a friend helpful.