在PHP中获取数组的索引值

I have an array:

我有一个数组:

$list = array('string1', 'string2', 'string3');

I want to get the index for a given value (i.e. 1 for string2 and 2 for string3)

我想获取给定值的索引(例如，string2的索引和string3的索引)

All I want is the position of the strings in the array

我想要的是数组中字符串的位置。

• string1 is 0
• string1是0
• string2 is 1
• string2相等是1
• string3 is 2
• string3是2

How to achieve this?

如何实现呢?

10 个解决方案

#1

array_search is the way to do it.

array_search就是这样做的。

From the docs:

从文档:

$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');

$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array);   // $key = 1;

You could loop over the array manually and find the index but why do it when there's a function for that. This function always returns a key and it will work well with associative and normal arrays.

您可以手动循环数组并找到索引，但是为什么要这样做呢?这个函数总是返回一个键，它可以很好地处理关联数组和普通数组。

#2

If you're only doing a few of them (and/or the array size is large), then you were on the right track with array_search:

如果您只做了其中的几个(并且/或数组大小较大)，那么您使用array_search的方向是正确的:

$list = array('string1', 'string2', 'string3');
$k = array_search('string2', $list); //$k = 1;

If you want all (or a lot of them), a loop will prob do you better:

如果你想要所有的(或很多)，循环会让你做得更好:

foreach ($list as $key => $value) {
    echo $value . " in " . $key . ", ";
}
// Prints "string1 in 0, string2 in 1, string3 in 2, "

#3

Other folks have suggested array_search() which gives the key of the array element where the value is found. You can ensure that the array keys are contiguous integers by using array_values():

另一些人建议使用array_search()，它提供查找值的数组元素的键。可以使用array_values()确保数组键是连续整数:

$list = array(0=>'string1', 'foo'=>'string2', 42=>'string3');
$index = array_search('string2', array_values($list));
print "$index\n";

// result: 1

You said in your question that array_search() was no use. Can you explain why? What did you try and how did it not meet your needs?

您在您的问题中说array_search()没有用。你能解释一下为什么?你试过什么，它怎么不满足你的需要?

#4

// or considering your array structure:

//或考虑数组结构:

$array = array(
  'string1' => array('a' => '', 'b' => '', 'c' => ''),
  'string2' => array('a' => '', 'b' => '', 'c' => ''),
  'string3' => array('a' => '', 'b' => '', 'c' => ''),
);

// you could just

/ /你可以

function findIndexOfKey($key_to_index,$array){
  return array_search($key_to_index,array_keys($array));
}

// executed

/ /执行

print "\r\n//-- Method 1 --//\r\n";
print '#index of: string1 = '.findIndexofKey('string1',$array)."\r\n";
print '#index of: string2 = '.findIndexofKey('string2',$array)."\r\n";
print '#index of: string3 = '.findIndexofKey('string3',$array)."\r\n";

// alternatively

/ /或者

print "\r\n//-- Method 2 --//\r\n";
print '#index of: string1 = '.array_search('string1',array_keys($array))."\r\n";
print '#index of: string2 = '.array_search('string2',array_keys($array))."\r\n";
print '#index of: string3 = '.array_search('string3',array_keys($array))."\r\n";

// recursersively

/ / recursersively

print "\r\n//-- Method 3 --//\r\n";
foreach(array_keys($array) as $key => $value){
  print '#index of: '.$value.' = '.$key."\r\n";
}

// outputs

/ /输出

//-- Method 1 --//
#index of: string1 = 0
#index of: string2 = 1
#index of: string3 = 2

//-- Method 2 --//
#index of: string1 = 0
#index of: string2 = 1
#index of: string3 = 2

//-- Method 3 --//
#index of: string1 = 0
#index of: string2 = 1
#index of: string3 = 2

#5

The problem is that you don't have a numerical index on your array.
Using array_values() will create a zero indexed array that you can then search using array_search() bypassing the need to use a for loop.

问题是数组中没有数值索引。使用array_values()将创建一个零索引数组，然后您可以使用array_search()搜索该数组，而无需使用for循环。

$list = array('string1', 'string2', 'string3');
$index = array_search('string2',array_values($list));

#6

Try the array_keys PHP function.

试试array_keys PHP函数。

$key_string1 = array_keys($list, 'string1');

#7

Could you be a little more specific?

你能说得更具体一点吗?

$key = array_search('string2',$list)

works fine for me. Are you trying to accomplish something more complex?

对我来说很不错。你想要完成更复杂的事情吗?

#8

This code should do the same as your new routine, working with the correct multi-dimensional array..

这段代码应该与您的新例程一样，使用正确的多维数组。

 $arr = array(
  'string1' => array('a' => '', 'b' => '', 'c' => ''),
  'string2' => array('a' => '', 'b' => '', 'c' => ''),
  'string3' => array('a' => '', 'b' => '', 'c' => '')
 );

 echo 'Index of "string2" = '. array_search('string2', array_keys($arr));

#9

array_search should work fine, just tested this and it returns the keys as expected:

array_search应该工作得很好，只是测试了一下，它会按预期返回键:

$list = array('string1', 'string2', 'string3');
echo "Key = ".array_search('string1', $list);
echo " Key = ".array_search('string2', $list);
echo " Key = ".array_search('string3', $list);

Or for the index, you could use

或者对于索引，你可以用

$list = array('string1', 'string2', 'string3');
echo "Index = ".array_search('string1', array_merge($list));
echo " Index = ".array_search('string2', array_merge($list));
echo " Index = ".array_search('string3', array_merge($list));

#10

$find="Topsite";
$list=array("Tope","Ajayi","Topsite","Infotech");
$list_count=count($list);
sort($list);
for($i=0;$i<$list_count;$i++)
{
    if($list[$i]==$find){
         $position=$i;
    }

}
echo $position;