Powershell - Hashtables
Hashtable stores key/value pairs in a hash table. When using a Hashtable, you specify an object that is used as a key, and the value that you want linked to that key. Generally we used String or numbers as keys.
This tutorial introduces how to declare hashtable variables, create hashtables, and process hashtable using its methods.
Declaring hashtable Variables
To use an hashtable in a program, you must declare a variable to reference the hashtable. Here is the syntax for declaring an hashtable variable −
Syntax
$hash = @{ ID = 1; Shape = "Square"; Color = "Blue"}
or
$hash = @{}
Note − Ordered dictionaries can be created using similar syntax. Ordered dictionaries maintain the order in which entries are added whereas hashtables do not.
Example
The following code snippets are examples of this syntax −
$hash = [ordered]@{ ID = 1; Shape = "Square"; Color = "Blue"}
Print the hashtable.
$hash
Output
Name Value
---- -----
ID 1
Color Blue
Shape Square
The hashtable values are accessed through the keys.
> $hash["ID"]
1
Processing Hashtable
Dot notation can be used to access hashtables keys or values.
> $hash.keys
ID
Color
Shape
> $hash.values
1
Blue
Square
Example
Here is a complete example showing how to create, initialize, and process hashtable −
$hash = @{ ID = 1; Shape = "Square"; Color = "Blue"}
write-host("Print all hashtable keys")
$hash.keys
write-host("Print all hashtable values")
$hash.values
write-host("Get ID")
$hash["ID"]
write-host("Get Shape")
$hash.Number
write-host("print Size")
$hash.Count
write-host("Add key-value")
$hash["Updated"] = "Now"
write-host("Add key-value")
$hash.Add("Created","Now")
write-host("print Size")
$hash.Count
write-host("Remove key-value")
$hash.Remove("Updated")
write-host("print Size")
$hash.Count
write-host("sort by key")
$hash.GetEnumerator() | Sort-Object -Property key
This will produce the following result −
Output
Print all hashtable keys
ID
Color
Shape
Print all hashtable values
1
Blue
Square
Get ID
1
Get Shape
print Size
3
Add key-value
Add key-value
print Size
5
Remove key-value
print Size
4
sort by key
Name Value
---- -----
Color Blue
Created Now
ID 1
Shape
Square
