When I want to check if something is in the array and get the key back, I use the array_search() function.
当我想检查数组中是否存在某些内容并获取密钥时，我使用了array_search（）函数。
Why is it when I compare the function to be exactly equal to true (=== true) it returns false, and when I compare it to not be exactly equal to false (!== false) it returns true?
为什么当我比较函数完全等于true（=== true）时它返回false，当我将它与不完全等于false（！== false）时它返回true？
<?php
if(array_search($value, $array) === true)
{
// Fails
}
if(array_search($value, $array) !== false)
{
// Succeeds
}
?>
Thanks in advance.
提前致谢。
4 个解决方案
#1
8
array_search returns you needle when a match is found. it returns false only when match is not found. This is why only the opposite works in your case.
找到匹配项时，array_search会返回指针。只有在找不到匹配时才返回false。这就是为什么在你的情况下只有相反的工作原因。
Returns the key for needle if it is found in the array, FALSE otherwise.
如果在数组中找到针，则返回针的键，否则返回FALSE。
#2
0
It will fail because if the call is succesfull it returns the key no true.
它将失败，因为如果调用成功，则返回键不为true。
false is returned if it isnt found so === false is ok
如果找不到，则返回false = = false false
from the manual:
从手册：
Returns the key for needle if it is found in the array, FALSE otherwise.
如果在数组中找到针，则返回针的键，否则返回FALSE。
#3
0
array_search() does not return true.
array_search（）不返回true。
If will only return false, if it can't find anything, otherwise it will return the key of the matched element.
如果只返回false，如果找不到任何内容，否则返回匹配元素的键。
According to the manual
根据手册
array_search — Searches the array for a given value and returns the corresponding key if successful ....
array_search - 在数组中搜索给定值，如果成功则返回相应的键....
Returns the key for needle if it is found in the array, FALSE otherwise.
如果在数组中找到针，则返回针的键，否则返回FALSE。
#4
0
Late to the party, but wanted to add some context / examples:
晚到派对，但想添加一些上下文/示例：
array_search will return the key (if the value is found) - which could be 0 - and will return FALSE if the value is not found. It never returns TRUE.
array_search将返回密钥（如果找到值） - 可能为0 - 如果未找到该值，则返回FALSE。它永远不会返回TRUE。
This code may sum it up better:
这段代码可以更好地总结：
// test array...
$array = [
0 => 'First Item',
1 => 'Second Item',
'x' => 'Associative Item'
];
// example results:
$key = array_search( 'First Item', $array ); // returns 0
$key = array_search( 'Second Item', $array ); // returns 1
$key = array_search( 'Associative Item', $array ); // returns 'x'
$key = array_search( 'Third Item', $array ); // returns FALSE
Since 0 is a falsey value, you wouldn't want to do something like if ( ! array_search(...) ) {... because it would fail on 0 index items.
因为0是假值，所以你不想做if（！array_search（...））{...因为它会在0索引项上失败。
Therefore, the way to use it is something like:
因此，使用它的方式如下：
$key = array_search( 'Third Item', $array ); // returns FALSE
if ( FALSE !== $key ) {
// item was found, key is in $index, do something here...
}
It's worth mentioning this is also true of functions like strpos and stripos, so it's a good pattern to get in the habit of following.
值得一提的是，strpos和stripos等功能也是如此，所以这是一个养成跟随习惯的好模式。
#1
8
array_search returns you needle when a match is found. it returns false only when match is not found. This is why only the opposite works in your case.
找到匹配项时，array_search会返回指针。只有在找不到匹配时才返回false。这就是为什么在你的情况下只有相反的工作原因。
Returns the key for needle if it is found in the array, FALSE otherwise.
如果在数组中找到针，则返回针的键，否则返回FALSE。
#2
0
It will fail because if the call is succesfull it returns the key no true.
它将失败，因为如果调用成功，则返回键不为true。
false is returned if it isnt found so === false is ok
如果找不到，则返回false = = false false
from the manual:
从手册：
Returns the key for needle if it is found in the array, FALSE otherwise.
如果在数组中找到针，则返回针的键，否则返回FALSE。
#3
0
array_search() does not return true.
array_search（）不返回true。
If will only return false, if it can't find anything, otherwise it will return the key of the matched element.
如果只返回false，如果找不到任何内容，否则返回匹配元素的键。
According to the manual
根据手册
array_search — Searches the array for a given value and returns the corresponding key if successful ....
array_search - 在数组中搜索给定值，如果成功则返回相应的键....
Returns the key for needle if it is found in the array, FALSE otherwise.
如果在数组中找到针，则返回针的键，否则返回FALSE。
#4
0
Late to the party, but wanted to add some context / examples:
晚到派对，但想添加一些上下文/示例：
array_search will return the key (if the value is found) - which could be 0 - and will return FALSE if the value is not found. It never returns TRUE.
array_search将返回密钥（如果找到值） - 可能为0 - 如果未找到该值，则返回FALSE。它永远不会返回TRUE。
This code may sum it up better:
这段代码可以更好地总结：
// test array...
$array = [
0 => 'First Item',
1 => 'Second Item',
'x' => 'Associative Item'
];
// example results:
$key = array_search( 'First Item', $array ); // returns 0
$key = array_search( 'Second Item', $array ); // returns 1
$key = array_search( 'Associative Item', $array ); // returns 'x'
$key = array_search( 'Third Item', $array ); // returns FALSE
Since 0 is a falsey value, you wouldn't want to do something like if ( ! array_search(...) ) {... because it would fail on 0 index items.
因为0是假值，所以你不想做if（！array_search（...））{...因为它会在0索引项上失败。
Therefore, the way to use it is something like:
因此，使用它的方式如下：
$key = array_search( 'Third Item', $array ); // returns FALSE
if ( FALSE !== $key ) {
// item was found, key is in $index, do something here...
}
It's worth mentioning this is also true of functions like strpos and stripos, so it's a good pattern to get in the habit of following.
值得一提的是，strpos和stripos等功能也是如此，所以这是一个养成跟随习惯的好模式。