blocks|key|294331|text|如果它们是相同的，我会使用count()，因为根据我的经验，它更常见，因此会导致较少的开发人员在阅读您的代码时会问"sizeof()，那是什么？“并且必须查阅文档。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|294332|我认为这意味着sizeof()不能像在C中那样工作(计算数据类型的大小)。它之所以明确提到这一点，可能是因为PHP是用C语言编写的，并为C函数(strlen()、printf()等)提供了许多同名的包装器。|294333|entityMap^0|D|7|1M|8|0|7|8|20|8|29|8|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|I|$]]

I would use <code>count()</code> if they are the same, as in my experience it is more common, and therefore will cause less developers reading your code to say "<code>sizeof()</code>, what is that?" and having to consult the documentation.

I think it means <code>sizeof()</code> does not work like it does in C (calculating the size of a datatype). It probably made this mention explicitly because PHP is written in C, and provides a lot of identically named wrappers for C functions (<code>strlen()</code>, <code>printf()</code>, etc)

blocks|key|3015682|text|根据phpbench的说法|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3015683|是否值得提前计算循环的长度？|3015684|//pre-calculate+the+size+of+array
$size+=+count($x);+//or+$size+=+sizeOf($x);

for+($i=0;+$i<$size;+$i%2B%2B)+{
++++//...
}

//don't+pre-calculate
for+($i=0;+$i<count($x);+$i%2B%2B)+{+//or+$i<sizeOf($x);
++++//...
}|code-block|syntax|javascript|3015685|给出了一个具有1000个键和1个字节值的循环。|3015686|++++++++++++++++++%2B---------%2B----------%2B
++++++++++++++++++%7C+count()+%7C+sizeof()+%7C
%2B-----------------%2B---------%2B----------%2B
%7C+With+precalc++++%7C+++++152+%7C++++++212+%7C
%7C+Without+precalc+%7C+++70401+%7C++++50644+%7C
%2B-----------------%2B---------%2B----------%2B++(time+in+µs)|3015687|所以我个人更喜欢使用count()而不是sizeof()来进行预计算。|3015688|entityMap|0|LINK|mutability|MUTABLE|url|http://phpbench.com/^0|2|8|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|13|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|15|8|@]|9|@]|C|$I|J]]|$1|O|3|P|5|6|7|16|8|@]|9|@]|C|$]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|C|$]]]|R|$S|$5|T|U|V|C|$W|X]]]]

According to <a href="http://phpbench.com/" rel="noreferrer">phpbench</a>:

Is it worth the effort to calculate the length of the loop in advance?

<pre><code>//pre-calculate the size of array
$size = count($x); //or $size = sizeOf($x);

for ($i=0; $i&lt;$size; $i++) {
 //...
}

//don't pre-calculate
for ($i=0; $i&lt;count($x); $i++) { //or $i&lt;sizeOf($x);
 //...
}
</code></pre>

A loop with 1000 keys with 1 byte values are given.

<pre class="lang-none prettyprint-override"><code> +---------+----------+
 | count() | sizeof() |
+-----------------+---------+----------+
| With precalc | 152 | 212 |
| Without precalc | 70401 | 50644 |
+-----------------+---------+----------+ (time in µs)
</code></pre>

So I personally prefer to use count() instead of sizeof() with pre calc.

blocks|key|294309|text|根据sizeof()的说法，它们是相同的|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|294310|在没有任何理由担心“更快”的情况下，始终为人类进行优化。对人类读者来说，哪一个更有意义？|294311|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/function.sizeof.php^0|2|8|2|8|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

They are identical according to <a href="http://php.net/manual/en/function.sizeof.php" rel="noreferrer"><code>sizeof()</code></a>

In the absence of any reason to worry about "faster", always optimize for the human. Which makes more sense to the human reader?

blocks|key|3229845|text|根据该网站的说法，sizeof()是count()的别名，所以他们应该运行相同的代码。也许sizeof()有一点开销，因为它需要将其解析为count()？不过，它应该是非常小的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3229846|entityMap^0|9|8|I|7|19|8|1X|7|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]|$9|O|A|P|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|G|$]]

According to the website, <code>sizeof()</code> is an alias of <code>count()</code>, so they should be running the same code. Perhaps <code>sizeof()</code> has a little bit of overhead because it needs to resolve it to <code>count()</code>? It should be very minimal though.

blocks|key|296291|text|我知道这很老，但我只想提一下PHP7.2中的I+tried+this：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|296292|<?php
//Creating+array+with+1+000+000+elements
$a+=+array();
for+($i+=+0;+$i+<+1000000;+%2B%2B$i)
{
++++$a[]+=+100;
}

//Measure
$time+=+time();
for+($i+=+0;+$i+<+1000000000;+%2B%2B$i)
{
++++$b+=+count($a);
}
print("1+000+000+000+iteration+of+count()+took+".(time()-$time)."+sec\n");

$time+=+time();
for+($i+=+0;+$i+<+1000000000;+%2B%2B$i)
{
++++$b+=+sizeof($a);
}
print("1+000+000+000+iteration+of+sizeof()+took+".(time()-$time)."+sec\n");
?>|code-block|syntax|javascript|296293|结果是：|296294|1+000+000+000+iteration+of+count()+took+414+sec
1+000+000+000+iteration+of+sizeof()+took+1369+sec|296295|所以只需使用count()即可。|style|CODE|296296|entityMap|0|LINK|mutability|MUTABLE|url|https://secure.php.net/manual/en/function.sizeof.php#123025^0|M|C|0|0|0|0|0|6|7|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|13|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|14|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|15|8|@$A|16|B|17|O|P]]|9|@]|C|$]]|$1|Q|3|-4|5|6|7|18|8|@]|9|@]|C|$]]]|R|$S|$5|T|U|V|C|$W|X]]]]

I know this is old but just wanted to mention that <a href="https://secure.php.net/manual/en/function.sizeof.php#123025" rel="noreferrer">I tried this</a> with PHP 7.2:

<pre><code>&lt;?php
//Creating array with 1 000 000 elements
$a = array();
for ($i = 0; $i &lt; 1000000; ++$i)
{
 $a[] = 100;
}

//Measure
$time = time();
for ($i = 0; $i &lt; 1000000000; ++$i)
{
 $b = count($a);
}
print("1 000 000 000 iteration of count() took ".(time()-$time)." sec\n");

$time = time();
for ($i = 0; $i &lt; 1000000000; ++$i)
{
 $b = sizeof($a);
}
print("1 000 000 000 iteration of sizeof() took ".(time()-$time)." sec\n");
?&gt;
</code></pre>

and the result was:

<pre><code>1 000 000 000 iteration of count() took 414 sec
1 000 000 000 iteration of sizeof() took 1369 sec
</code></pre>

So just use <code>count()</code>.

blocks|key|296272|text|sizeof()只是这里提到的count()的别名|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|296273|http://php.net/manual/en/function.sizeof.php|296274|entityMap|0|LINK|mutability|MUTABLE|url^0|0|8|F|7|0|0|18|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@]|D|@$9|U|A|V|1|W]]|E|$]]|$1|H|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|G]]]]

<code>sizeof()</code> is just an alias of <code>count()</code>
as mentioned here

<a href="http://php.net/manual/en/function.sizeof.php" rel="noreferrer">http://php.net/manual/en/function.sizeof.php</a>

blocks|key|294388|text|两者都用于对数组中的元素进行计数。sizeof()函数是PHP中使用的count()函数的别名。然而，count()函数比sizeof()更快、更好。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|294389|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Both are used to count elements in a array. sizeof() function is an alias of count() function used in PHP. However, count() function is faster and better than sizeof().

blocks|key|3229950|text|请使用count函数，这里是一个如何计算元素中数组的例子|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3229951|$cars+=+array("Volvo","BMW","Toyota");
echo+count($cars);|code-block|syntax|javascript|3229952|count()函数返回数组中元素的数量。|offset|length|style|CODE|3229953|sizeof()函数返回数组中元素的数量。|3229954|sizeof()函数是count()函数的别名。|3229955|entityMap^0|0|0|0|7|0|0|8|0|0|8|B|7|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@$I|Y|J|Z|K|L]]|9|@]|A|$]]|$1|O|3|P|5|6|7|10|8|@$I|11|J|12|K|L]|$I|13|J|14|K|L]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|R|$]]

Please use count function, Here is a example how to count array in a element

<pre><code>$cars = array("Volvo","BMW","Toyota");
echo count($cars);
</code></pre>

The <code>count()</code> function returns the number of elements in an array.

The <code>sizeof()</code> function returns the number of elements in an array.

The <code>sizeof()</code> function is an alias of the <code>count()</code> function.

To find the number of elements in a PHP <code>$array</code>, which is faster/better/stronger?

<code>count($array)</code> or <code>sizeof($array)</code> ?

<h2>Edit</h2>

Thanks to Andy Lester, I have refined my question to mean from a multilingual perspective. The manual commenters say 

<blockquote>
 "[sizeof] does not mean the same in
 many other languages based on C"
</blockquote>

Is this true?

PHP array: count or sizeof?

要找出PHP $array中元素的数量，哪个更快/更好/更强？count($array)还是sizeof($array)？编辑多亏了Andy Lester，我将我的问题从多语言的角度进行了改进。手册评论者说 "sizeof在许多其他基于C的语言中并不意味着相同“这是真的吗？

问PHP数组: count还是sizeof？
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