strlen on array returns 5 in php

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-

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

'texben' so it may output - 6
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)

Together with this code you should be getting an "array conversion to string" warning message. When you get such a warning you are almost always doing something you should not be. — Jon, Jul 01 '13 at 11:14
You need to configure your development box to display all error messages: [fiddle](http://3v4l.org/I3KO1). — Álvaro González, Jul 01 '13 at 11:15
@Jon I executed it here ..but no warnings as u mentioned?? http://codepad.org/4D9pC447 — Trialcoder, Jul 01 '13 at 11:15
@Trialcoder - See [updated codepad](http://codepad.org/vgzV1Hcc). — Álvaro González, Jul 01 '13 at 11:16

score 10 · Accepted Answer · edited Jun 20 '20 at 09:12

10

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.

edited Jun 20 '20 at 09:12

Community

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answered Jul 01 '13 at 11:12

MrCode

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String is an array of characters. It is strange that strlen() return null for all arrays but array of char-s. :) – Yevgeniy Afanasyev Aug 25 '15 at 03:33

score 3 · Answer 2 · answered Jul 01 '13 at 11:13

3

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

answered Jul 01 '13 at 11:13

Mark Baker

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Why complicate things when: `strlen(implode($a))` will work fine? – Leri Jul 01 '13 at 11:18
Well if the OP wants an array of individual string lengths, the first solution isn't complicating things; the second is a natural extension from that, though I'll conceded it is more complicated than implode() and strlen() – Mark Baker Jul 01 '13 at 11:22
@MarkBaker +1 for two new methods..i will investigate more abt these two soon :) – Trialcoder Jul 01 '13 at 11:23
@MarkBaker It depends on what OP wants. If only requirement is to count characters in array with this structure I'd go with implode. Personally I hate passing closures as strings (i.e. passing names of pre-defined functions) it makes debugging nightmare in large projects. – Leri Jul 01 '13 at 11:27
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@PLB - though using a closure as the first argument simply to do the strlen is even more ugly – Mark Baker Jul 01 '13 at 11:30
I just tried a comparison of the 2 methods on an array of 40k elements. `strlen(implode($a))` was about 12 times faster than `array_sum(array_map('strlen',$a))` so definitely better to use the `strlen(implode())` method! – Redzarf Apr 12 '18 at 14:01

score 2 · Answer 3 · answered Jul 01 '13 at 11:13

2

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;

answered Jul 01 '13 at 11:13

Sirko

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strlen on array returns 5 in php

3 Answers3