blocks|key|1160721|text|如果你使用array_keys()，PHP会给你一个数组，里面只有键：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1160722|$keys+=+array_keys($arr);
foreach($keys+as+$key)+{
++++echo($key);
}|code-block|syntax|javascript|1160723|或者，您可以执行以下操作：|1160724|foreach($arr+as+$key+=>+$value)+{
++++echo($key);
}|1160725|entityMap^0|5|C|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

If you use <code>array_keys()</code>, PHP will give you an array filled with just the keys:

<pre><code>$keys = array_keys($arr);
foreach($keys as $key) {
 echo($key);
}
</code></pre>

Alternatively, you can do this:

<pre><code>foreach($arr as $key =&gt; $value) {
 echo($key);
}
</code></pre>

blocks|key|1160744|text|下面的代码将允许您同时获取键和值。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1160745|foreach+($arr+as+$key+=>+$value)
{
++echo($key);
}|code-block|syntax|javascript|1160746|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The following will allow you to get at both the key and value at the same time.

<pre><code>foreach ($arr as $key =&gt; $value)
{
 echo($key);
}
</code></pre>

blocks|key|1160794|text|foreach($array+as+$k+=>+$v)|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1160795|其中$k是键，$v是值|unstyled|1160796|或者，如果只是需要密钥，则使用array_keys()|1160797|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>foreach($array as $k =&gt; $v)
</code></pre>

Where $k is the key and $v is the value

Or if you just need the keys use array_keys()

blocks|key|1376122|text|您可以执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1376123|foreach+($arr+as+$key+=>+$value)+{
+echo+$key;
}|code-block|syntax|javascript|1376124|如PHP+docs中所述。|offset|length|1376125|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/control-structures.foreach.php^0|0|0|1|8|0|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]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

You can do:

<pre><code>foreach ($arr as $key =&gt; $value) {
 echo $key;
}
</code></pre>

As described in <a href="http://php.net/manual/en/control-structures.foreach.php" rel="noreferrer">PHP docs</a>.

blocks|key|1376150|text|+foreach($arr+as+$key=>$value){
++++echo($key);++++//+key
+}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1376151|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> foreach($arr as $key=&gt;$value){
 echo($key); // key
 }
</code></pre>

blocks|key|1376178|text|使用$key+=>+$val获取密钥：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1376179|<?php

$arr+=+array(
++++1+=>+"Value1",
++++2+=>+"Value2",
++++10+=>+"Value10",
);

foreach+($arr+as+$key+=>+$val)+{
+++print+"$key\n";
}

?>|code-block|syntax|javascript|1376180|entityMap^0|2|C|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Use <code>$key =&gt; $val</code> to get the keys:

<pre><code>&lt;?php

$arr = array(
 1 =&gt; "Value1",
 2 =&gt; "Value2",
 10 =&gt; "Value10",
);

foreach ($arr as $key =&gt; $val) {
 print "$key\n";
}

?&gt;
</code></pre>

blocks|key|1376251|text|虽然可以说这种方法不那么清晰，但它的速度大约快3.5倍(至少在我用来测试的盒子上是这样)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1376252|$foo+=+array(
++++1+=>+"Value1",
++++2+=>+"Value2",
++++10+=>+"Value10"
);
while($bar+=+each($foo)){
++++echo+$bar[0]+.+"+=>+"+.+$bar[1];
}|code-block|syntax|javascript|1376253|我可以想象这是因为foreach在迭代数组之前复制了整个数组。|1376254|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

While arguably being less clear this method is faster by roughly a factor of roughly 3.5 (At least on the box I used to test)

<pre><code>$foo = array(
 1 =&gt; "Value1",
 2 =&gt; "Value2",
 10 =&gt; "Value10"
);
while($bar = each($foo)){
 echo $bar[0] . " =&gt; " . $bar[1];
}
</code></pre>

I would imagine that this is due to the fact the foreach copies the entire array before iterating over it.

blocks|key|1161036|text|我使用以下循环从关联数组中获取键和值|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1161037|foreach+($array+as+$key+=>+$value)
{
++echo+"$key+=+$value";
}|code-block|syntax|javascript|1161038|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I use the following loop to get the key and value from an associative array

<pre><code>foreach ($array as $key =&gt; $value)
{
 echo "&lt;p&gt;$key = $value&lt;/p&gt;";
}
</code></pre>

blocks|key|1161091|text|没有人回答常规的for循环？有时我发现它更具可读性，比起foreach，我更喜欢for|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1161092|所以就是这样：|1161093|$array+=+array('key1'+=>+'value1',+'key2'+=>+'value2');+

$keys+=+array_keys($array);

for($i=0;+$i+<+count($keys);+%2B%2B$i)+{
++++echo+$keys[$i]+.+'+'+.+$array[$keys[$i]]+.+"\n";
}

/*
++prints:
++key1+value1
++key2+value2
*/|code-block|syntax|javascript|1161094|entityMap^0|8|3|S|7|14|3|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

Nobody answered with regular <code>for</code> loop? Sometimes I find it more readable and prefer <code>for</code> over <code>foreach</code> 
So here it is:

<pre><code>$array = array('key1' =&gt; 'value1', 'key2' =&gt; 'value2'); 

$keys = array_keys($array);

for($i=0; $i &lt; count($keys); ++$i) {
 echo $keys[$i] . ' ' . $array[$keys[$i]] . "\n";
}

/*
 prints:
 key1 value1
 key2 value2
*/
</code></pre>

blocks|key|1161111|text|<?php
$names+=+array("firstname"=>"maurice",
+++++++++++++++"lastname"=>"muteti",+
+++++++++++++++"contact"=>"7844433339");

foreach+($names+as+$name+=>+$value)+{
++++echo+$name."+".$value."";
}

print_r($names);
?>|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1161112|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>&lt;?php
$names = array("firstname"=&gt;"maurice",
 "lastname"=&gt;"muteti", 
 "contact"=&gt;"7844433339");

foreach ($names as $name =&gt; $value) {
 echo $name." ".$value."&lt;/br&gt;";
}

print_r($names);
?&gt;
</code></pre>

blocks|key|1376398|text|如果使用嵌套的foreach()函数，则会反复打印外部数组的键，直到内部数组值结束。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1376399|<?php+

$myArray+=+['key_1'+=>+['value_1',+'value12'],
++++++++++++'key_2'+=>+['value_2',+'value22'],+
++++++++++++'key_3'+=>+['value_3',+'value32']
+++++++++++];

$keysOfMyArray+=+array_key($myArray);

for+($x+=+0;+$x+<+count($myArray);+$x%2B%2B){
+++++++print+"\t".$keysOfMyArray[$x]."\t\t".implode("\t\t",$myArray[$keysOfMyArray[$x]]."\n");
}

?>|code-block|syntax|javascript|1376400|entityMap^0|7|9|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

If you use nested <code>foreach()</code> function, outer array's keys print again and again till inner array values end.

<pre><code>&lt;?php 

$myArray = ['key_1' =&gt; ['value_1', 'value12'],
 'key_2' =&gt; ['value_2', 'value22'], 
 'key_3' =&gt; ['value_3', 'value32']
 ];

$keysOfMyArray = array_key($myArray);

for ($x = 0; $x &lt; count($myArray); $x++){
 print "\t".$keysOfMyArray[$x]."\t\t".implode("\t\t",$myArray[$keysOfMyArray[$x]]."\n");
}

?&gt;
</code></pre>

My associative array: 

<pre><code>$arr = array(
 1 =&gt; "Value1",
 2 =&gt; "Value2",
 10 =&gt; "Value10"
);
</code></pre>

Using the following code, <code>$v</code> is filled with <code>$arr</code>'s values

<pre><code> foreach($arr as $v){
 echo($v); // Value1, Value2, Value10
 }
</code></pre>

How do I get <code>$arr</code>'s keys instead?

<pre><code> foreach(.....){
 echo($k); // 1, 2, 10
 }
</code></pre>

How to loop through an associative array and get the key?

我的关联数组：$arr = array(   1 => "Value1",   2 => "Value2",   10 => "Value10");使用以下代码，用$arr的值填充$v foreach($arr as $v){    echo($v);    // Value1, Value2, Value10 }我怎...

问如何遍历关联数组并获取键？
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