strlen on array在php中返回5

Question

From the docs -

int strlen ( string $string )

it takes string as a parameter, now when I am doing this-

$a = array('tex','ben');
echo strlen($a);

Output - 5

However I was expecting, two type of output-

1. If it is an array, php might convert it into string so the array will become-

   'texben' so it may output - 6

2. If 1st one is not it will convert it something like this -

   "array('tex','ben')" so the expected output should be - 18 (count of all items)

But every time it output- 5

My consideration from the output is 5 from array word count but I am not sure. If it is the case how PHP is doing this ?(means counting 5)

Answer 1

The function casts the input as a string, and so arrays become Array , which is why you get a count of 5.

It's the same as doing:

$a = array('tex','ben');

echo (string)$a; // Array
var_dump((string)$a); // string(5) "Array"

This is the behavior prior to PHP 5.3. However in PHP 5.3 and above, strlen() will return NULL for arrays.

From the Manual :

strlen() returns NULL when executed on arrays, and an E_WARNING level error is emitted.

Prior [to 5.3.0] versions treated arrays as the string Array, thus returning a string length of 5 and emitting an E_NOTICE level error.

Answer 2

Use

$a = array('tex','ben');
$lengths = array_map('strlen',$a);

to get an array of individual lengths, or

$a = array('tex','ben');
$totalLength = array_sum(array_map('strlen',$a));

to get the total of all lengths

Answer 3

The array is implicitly converted to a string. In PHP this yields the output Array , which has 5 letters as strlen() told you.

You can easily verify this, by running this code:

$a = array('tex','ben');
echo $a;