My associative array:
$arr = array(
1 => "Value1",
2 => "Value2",
10 => "Value10"
);
Using the following code, $v
is filled with $arr
's values
foreach($arr as $v){
echo($v); // Value1, Value2, Value10
}
How do I get $arr
's keys instead?
foreach(.....){
echo($k); // 1, 2, 10
}
This question is related to
php
loops
associative-array
foreach($arr as $key=>$value){
echo($key); // key
}
If you use array_keys()
, PHP will give you an array filled with just the keys:
$keys = array_keys($arr);
foreach($keys as $key) {
echo($key);
}
Alternatively, you can do this:
foreach($arr as $key => $value) {
echo($key);
}
If you use nested foreach()
function, outer array's keys print again and again till inner array values end.
<?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); $x++){
print "\t".$keysOfMyArray[$x]."\t\t".implode("\t\t",$myArray[$keysOfMyArray[$x]]."\n");
}
?>
foreach($array as $k => $v)
Where $k is the key and $v is the value
Or if you just need the keys use array_keys()
Nobody answered with regular for
loop? Sometimes I find it more readable and prefer for
over foreach
So here it is:
$array = array('key1' => 'value1', 'key2' => 'value2');
$keys = array_keys($array);
for($i=0; $i < count($keys); ++$i) {
echo $keys[$i] . ' ' . $array[$keys[$i]] . "\n";
}
/*
prints:
key1 value1
key2 value2
*/
Use $key => $val
to get the keys:
<?php
$arr = array(
1 => "Value1",
2 => "Value2",
10 => "Value10",
);
foreach ($arr as $key => $val) {
print "$key\n";
}
?>
<?php
$names = array("firstname"=>"maurice",
"lastname"=>"muteti",
"contact"=>"7844433339");
foreach ($names as $name => $value) {
echo $name." ".$value."</br>";
}
print_r($names);
?>
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)
$foo = array(
1 => "Value1",
2 => "Value2",
10 => "Value10"
);
while($bar = each($foo)){
echo $bar[0] . " => " . $bar[1];
}
I would imagine that this is due to the fact the foreach copies the entire array before iterating over it.
Oh I found it in the PHP manual.
foreach ($array as $key => $value){
statement
}
The current element's key will be assigned to the variable $key on each loop.
The following will allow you to get at both the key and value at the same time.
foreach ($arr as $key => $value)
{
echo($key);
}
I use the following loop to get the key and value from an associative array
foreach ($array as $key => $value)
{
echo "<p>$key = $value</p>";
}
Source: Stackoverflow.com