可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试):
问题:
I'm trying to complete my assignment and this is the last thing to do now.
I know if I want to print the whole array I can just use foreach
and many different method to print the entire array
foreach($v as $k=>$variable_name) { echo "<p> This is index of $k. value is $variable_name <br/></p>";}
But what if I want to only print each index separately?
I want to do the error message under each form so that is why I want each of them separate.
I tried with $v[0]
and nothing appear.
is there a trick or something am I missing?
回答1:
If you're talking about an associative array, you need to fetch the index directly:
Example:
$array = array ('test' => 'value1', 'test2' => 'value2');
echo $array['test']; // value1
You can do a print_r($array) to see the array structure nicely formatted:
<pre>
<?php print_r($array);?>
</pre>
What you're doing instead is fetch a value by its numerical index, like in
$array = array('test','test2','test3');
echo $array[0]; // test
On a further note, you can check beforehand if a key exists using array_key_exists():
var_dump(array_key_exists('test2',$array)); // (bool) TRUE
回答2:
array_keys() will print indexes in array.
print_r(array_keys($arr));
回答3:
I believe you're looking for this: http://php.net/manual/en/function.array-keys.php
Try (from the above page):
<?php
$array = array(0 => 100, "color" => "red");
print_r(array_keys($array));
$array = array("blue", "red", "green", "blue", "blue");
print_r(array_keys($array, "blue"));
$array = array("color" => array("blue", "red", "green"),
"size" => array("small", "medium", "large"));
print_r(array_keys($array));
?>
回答4:
You can use php array_keys function to get all keys. If Its Associative Array,
$array = array("color" => array("blue", "red", "green"),
"size" => array("small", "medium", "large"));
print_r(array_keys($array));
output will be :
Array
(
[0] => color
[1] => size
)
Other way is :
if(is_array($v){
foreach($v as $k=>$value) {
echo "<br/>". $k ; // $k is the key
}
}
回答5:
If you're using the foreach
loop then you're probably using an associative array (i.e. $v['inputName']
) So, using $v[0]
wouldn't work because the indexes aren't defined by numbers - they are defined by lettering. You could use a foreach
loop to then associate all the values to the numbered indexes and then us it like that.
$x = array();
foreach($v as $key=>$value) {
$x[count($x)] = $key;
}
echo $x[0];
In that case $x[0]
would work
回答6:
use print_r function to print the array :
print_r($array)