Exactly one occurence of value in array - php

Question

I'm trying to find a native php function which returns true if there is exactly one occurrence of any given element in an array.
For example:
$searchedForValue = 3;
$array1 = [1,2,3,4,5,6];
$array2 = [1,2,3,3,4,5];
$array3 = [1,2,4,5,6];
oneOccurrence($array1,$searchedForValue);
oneOccurrence($array2,$searchedForValue);
oneOccurrence($array3,$searchedForValue);
This should return:
true
false
false
Cheers

Answer 1

You should use array_count_values() here.
$array_values = array_count_values($array2);
This will return an array. Key denotes each element of $array2 and value denotes frequency of each element.:
Array (
[1] => 1
[2] => 1
[3] => 2 // Denotes 3 appears 2 times
[4] => 1
[5] => 1
)
if (#$array_values[$searchedForValue] == 1) {
echo "True";
} else {
echo "False";
}

Answer 2

This does what you want. Bare in mind, echoing oneOccurence won't output 'true' or 'false', it returns a boolean.
function oneOccurrence ($arr, $val) {
$occurrences = [];
foreach ($arr as $v) {
if ($v == $val) {
$occurrences[] = $v;
}
}
return count($occurrences) == 1;
}
P.S echo doesn't need brackets as it's a PHP construct.

Answer 3

A small utility function - count array values using array_count_values and then if the search key exists and if its count is exactly 1, return true otherwise false:
function oneOccurrence($array, $searchValue) {
$array = array_count_values($array);
return (array_key_exists($searchValue, $array) && $array[$searchValue]==1)?true:false;
}
Check EVAL

Answer 4

Since you are searching for one occurrence: http://codepad.org/cZImb4FI
Use array_count_values()
<?php
$searchedForValue = 3;
$array1 = array(1,2,3,4,5,6);
$array2 = array(1,2,3,3,4,5);
$array3 = array(1,2,4,5,6);
$arr = array($array1,$array2 ,$array3);
function array_count_values_of($value, $array) {
$counts = array_count_values($array);
return $counts[$value];
}
foreach($arr as $ar){
if( array_count_values_of($searchedForValue,$ar)==1){echo "true";}else{echo "false";}
}
?>
output
true false false

Answer 5

//In Php in_array() function is provided..
$searchedForValue = 3;
$array1 = array(1,2,3,4,5,6);
$array2 = array(1,2,3,3,4,5);
$array3 = array(1,2,4,5,6);
if(in_array($searchedForValue,$array1))
{
echo "true";
}
else
{
echo "false";
}
if(in_array($searchedForValue,$array2))
{
echo "true";
}
else
{
echo "false";
}
if(in_array($searchedForValue,$array3))
{
echo "true";
}
else
{
echo "false";
}