You can use the following methods in PowerShell to find either the union or intersection of two arrays:
Method 1: Find Union of Two Arrays
$first_array + $second_array | Select -Unique
This particular example will return the union of the arrays named $first_array and $second_array, which represents all of the unique values that belong to either array.
Method 2: Find Intersection of Two Arrays
$first_array | Where {$second_array -contains $_}
This particular example will return the intersection of the arrays named $first_array and $second_array, which represents all of the unique values that belong in both arrays.
The following examples shows how to use each of these methods in practice.
Example 1: Find Union of Two Arrays in PowerShell
We can use the following syntax to define two arrays, array1 and array2, and then find the union of those two arrays:
$first_array = @(1, 2, 3, 4, 5)
$second_array = @(3, 4, 5, 6, 7)
$first_array + $second_array | Select -Unique
The following screenshot shows how to use this syntax in practice:
We can see that this returns all unique values that belong to either $first_array or $second_array:
- 1, 2, 3, 4, 5, 6, 7
Example 2: Find Intersection of Two Arrays in PowerShell
We can use the following syntax to define two arrays, array1 and array2, and then find the intersection of those two arrays:
$first_array = @(1, 2, 3, 4, 5)
$second_array = @(3, 4, 5, 6, 7)
$first_array | Where {$second_array -contains $_}
The following screenshot shows how to use this syntax in practice:
We can see that this returns all unique values that belong to both $first_array and $second_array:
- 3, 4, 5
Related Tutorials
The following tutorials explain how to perform other common tasks in PowerShell:
PowerShell: How to Compare Two Arrays
PowerShell: How to Remove Duplicate Values from Array
PowerShell: Check if String Exists in List of Strings
