★ wanayoo — archive 1999 http://www.php.net/manual/de/function.sizeof.php

Nouvelle recherche | Portail wanayoo

PHP Home Page

	Arrays
		array
		array_count_values
		array_flip
		array_keys
		array_merge
		array_merge_recursive
		array_multisort
		array_pad
		array_pop
		array_push
		array_rand
		array_reverse
		array_shift
		array_slice
		array_splice
		array_unshift
		array_values
		array_walk
		arsort
		asort
		compact
		count
		current
		each
		end
		extract
		in_array
		key
		krsort
		ksort
		list
		next
		pos
		prev
		range
		reset
		rsort
		shuffle
		sizeof
		sort
		uasort
		uksort
		usort

Manual: sizeof

Updated
Sun, 06 Aug 2000

sizeof

(PHP3 , PHP4 )

sizeof -- Get the number of elements in an array

Description

int sizeof (array array)

Returns the number of elements in the array.

See also: count()

User Contributed Notes: sizeof

HSH@taxon.demon.nl
25-Jun-1999 04:09

If you're used to 'true' arrays in other languages, this function may trip you up: it returns the number of elements in the array that is actually filled. If only myarray[2] has a value and mayarray[0] and myarray[1] do not, then <B>sizeof(mayarray)</B> will return <B>1</B>, not 3. This is caused by the fact that arrays here are actually always associative arrays. If you're filling some elements of the array using an index counter, you may want to save the counter value for the highest element to access the array later on.

HSH@taxon.demon.nl
25-Jun-1999 04:18

...and BTW: <B>count()</B> does the same thing: it also returns only the number of actually <I>filled</I>elements.

christian@schmidt.net
08-Dec-1999 10:50

Note that sizeof($x), where $x is a variable that is set but is not an array sizeof, returns 1. Hence you have to be careful e.g. when you are dealing with arrays of multiple dimensions. for ($i = 0; $i < sizeof($myarray[$j]); $i++) will not work as expected if $myarray[$j] hasn't been assigned a value (i.e. an array value).

sgarner@expio.co.nz
10-Jan-2000 09:22

If some elements in your array are not set, then sizeof() and count() will not return the index of the last element, but will return the number of set elements. To find the index of the last element in the array: <pre> end($yourArray); $index = key($yourArray); </pre> ... Where $yourArray is the array you want to find the last index ($index) of.

cu@ulakbim.gov.tr
04-Feb-2000 09:12

Remember, PHP code is interpreted so sizeof() is always evaluated in place and everytime. So a very simple code like below can blow up your server box (tested :) <PRE> <? $arr= range(0,19); echo sizeof($arr)." "; for($i=0; $i<=sizeof($arr); $i++) { // <= is used intentionally $arr[$i] = ""; echo sizeof($arr)." Passing over #".$i." \n"; } ?> </PRE> The assignment $arr[$i] when used in conjunction with <= in the for loop causes the assignment to add an extra element to the end of the array. So when the for-condition is next time checked when $i=20, sizeof($arr) will yield 21, the next time 22, and so on. So the program in fact starts to leak heavily and very rapidly. You can instead use: <PRE> <? //... $c = sizeof($arr); for($i = 0; $i <= $c; $i++) { // <= is used intentionally again ... ?> </PRE> This one will add the 21th element, but will stop then. No leak at all...

james@totalgeek.org
19-May-2000 09:13

Once again a user post on php.net saved my butt! I was doing exactly what the comment above said not to do. :)

Updated
Sun, 06 Aug 2000

Located in
United States

Elements of this website are subject to copyright.
Questions about installing or using PHP should be directed to one of the mailing lists.
Only questions about the website should be directed to webmaster@php.net.