Array search, with multiple key relations x value

Question

Example scenario

I got the following Array:

array (
  0 => 
  array (
    'A' => 'X',
    'B' => 'Y',
    'C' => 1,
  ),
  1 => 
  array (
    'A' => 'X',
    'B' => 'Y',
    'C' => 2,
  ),
  2 => 
  array (
    'A' => 'X',
    'B' => 'W',
    'C' => 1,
  ),
  3 => 
  array (
    'A' => 'X',
    'B' => 'W',
    'C' => 3,
  ),
)

---

Goal

I would like to search, if the array permissoes contains a array, which meets the 3 specific values, for example:

A = X
B = Y
C = 2
# Encontrará o array [1]

A = X
B = Y
C = 3
# Não encontrará nenhum valor

---

Doubt

• What is the best way to search?

Answer 1

You just build one array similar to what is in the permissions list and use the function array_search:

$A = 'X';
$B = 'Y';
$C = 2;

$indice = array_search(compact('A', 'B', 'C'), $permissoes);

The function compact will generate a array ['A' => 'X', 'B' => 'Y', 'C' => 2], looking for this array in the permissions list. If found, the index of the first occurrence is returned; otherwise it will be returned false.

$A = 'X';
$B = 'Y';
$C = 2;

if (($indice = array_search(compact('A', 'B', 'C'), $permissoes)) !== false) {
    echo "Permissões encontradas no índice {$indice}";
} else {
    echo "Permissões não encontradas";
}

^{See working on Repl.it | Ideone}

Answer 2

You can use the function array_search to search for values within the array. But if you don’t need to know where the element is, the function in_array serves the purpose.

The behavior of comparisons between arrays will depend on whether the comparison is strict or not. Where normal comparison checks whether arrays have the same key/value pairs and restricted comparison also checks if they are in the same order. Ex.:

$a = ['a' => 1, 'b' => 2];
$b = ['b' => 2, 'a' => 1];

$a == $b;  // true
$a === $b; // false

That said, just use the in_array:

<?php

$permissoes = [
    ["A" => "X", "B" => "Y", "C" => 1],
    ["A" => "X", "B" => "Y", "C" => 2],
    ["A" => "X", "B" => "W", "C" => 1],
    ["A" => "X", "B" => "W", "C" => 3],
];

$existente = ["A" => "X", "B" => "Y", "C" => 2];
$inexistente = ["A" => "X", "B" => "Y", "C" => 3];

// Printa: "Tem permissão"
if (in_array($existente, $permissoes)) {
    echo "Tem permissão";
} else {
    echo "Não tem permissão";
}

// Printa: "Não tem permissão"
if (in_array($inexistente, $permissoes)) {
    echo "Tem permissão";
} else {
    echo "Não tem permissão";
}

^{Repl.it with the code working}

It is important to remember that the method array_search returns the index of the element found in the array or false if the element is not found. So remember to make a strict comparison, because if the element is in the first position the result will be zero, which is a value falsy (if you use in_array this is not a problem). Ex:

<?php

$a = [1, 2, 3, 4];

$result = array_search(1, $a);

// Printa: "Não encontrado"
if ($result) {
    echo "Encontrado";
} else {
    echo "Não encontrado";
}