How to use PHP in_array with associative array?

问题

Is there any php function such as in_array for associative arrays you get by the mysql function "mysql_fetch assoc" ?

For example, if I have an $array that looks like this:

array(0=>(array(ID=>1, name=>"Smith"), 1=>(array(ID=>2, name=>"John"))

Can I do something like in_array(key,value,array)?

Or in my case, if I am looking for the ID value of "1", in_array("ID",1,$array).

This is my solution, comment on it if you think it's the right way:

function in_assoc_array($key,$value,$array)
{
    if (empty($array))
        return false;
    else
    {
        foreach($array as $a)
        {
            if ($a[$key] == $value)
                return true;
        }
        return false;
    }
}

回答1:

Try this..... You can use this function for any depth of the associated array. Just contraint to this function is that the key value would not be repeat any where in array.

<?php 
function is_in_array($array, $key, $key_value){
      $within_array = 'no';
      foreach( $array as $k=>$v ){
        if( is_array($v) ){
            $within_array = is_in_array($v, $key, $key_value);
            if( $within_array == 'yes' ){
                break;
            }
        } else {
                if( $v == $key_value && $k == $key ){
                        $within_array = 'yes';
                        break;
                }
        }
      }
      return $within_array;
}
$test = array(
                0=> array('ID'=>1, 'name'=>"Smith"), 
                1=> array('ID'=>2, 'name'=>"John")
        );
print_r(is_in_array($test, 'name', 'Smith'));
?>

回答2:

In your case, I wonder if simply using isset() makes more sense, i.e.

isset($a[$key])

回答3:

You can't do it directly on nested arrays.. You need to nest it down a bit and then do it.

<?php
$arr=array(0=>array('ID'=>1, 'name'=>"Smith"), 1=>array('ID'=>2, 'name'=>"John"));

foreach($arr as $arr1)
{
    if(in_array(1,$arr1))
    {
       echo "Yes found.. and the correspoding key is ".key($arr1)." and the employee is ".$arr1['name'];
    }
}

OUTPUT :

Yes found.. and the correspoding key is ID and the employee is Smith

回答4:

First you must know which part of the associative array you're going to use as haystack in in_array function. Then you can use in_array without additional code.

Example with values :

<?php
$assoc = array(1 => "apple", 2 => "banana", 3 => "lemon", 4 => "pear");
$haystack = array_values($assoc);
echo "<p>" . print_r($assoc, true) . "</p>";

$needle = 'banana';
$find = (in_array($needle, $haystack)) ? 'TRUE' : 'FALSE';
echo "<p>$needle : $find</p>";

$needle = 'cherry';
$find = (in_array($needle, $haystack)) ? 'TRUE' : 'FALSE';
echo "<p>$needle : $find</p>";
?>

Results in :

Array ( [1] => apple [2] => banana [3] => lemon [4] => pear )

banana : TRUE

cherry : FALSE

回答5:

The sample formule, using class and methods:

class VerifyInArray
{
 public function getMyCollection($field, $collection)
 {
     $list = array();
     if (count($collection)) {
        foreach ($collection as $k => $val) {
            $list[] = $val[$field];
        }
     }
     return $list;
 }

public function inMyArray($collection, $field, $findValue)
{
    if (isset($collection[0])) {
        if (array_key_exists($field, $collection[0]) == false) {
           return 'no'; 
        }
    }

    if (in_array($findValue, $this->getMyCollection($field, $collection))) {
        return 'ok';
    }
    return 'no';
}

public function displayInArray($collection, $attr, $value)
{
   return 'search result: '. $this->inMyArray($collection, $attr, $value);
}

}
$src = new VerifyInArray();

 $collection = array(
         array(
               'ID' => 1, 
               'name' => 'Smith'
         ), 
         array(
               'ID' => 2, 
               'name' => 'John'
         )
    );
echo $src->displayInArray($collection, 'ID', 2). "\n<br>" .
     $src->displayInArray($collection, 'ID', 0);

Model in ideone

来源：https://stackoverflow.com/questions/21809116/how-to-use-php-in-array-with-associative-array

标签

php

associative-array