Professional Windows® PowerShell

11.2. Associative Arrays

An associative array is a data structure intended to store paired keys and values. An associative array can be visualized as a two-column table, with one column holding the key and the other column holding the corresponding value in the same row. An associative array is used to store two related pieces of information. In Windows PowerShell an associative array is stored as a hash table (a System.Collections.HashTable object) in order to achieve good performance.

The expression which defines the key-value pairs in an associative array begins with an @ sign and is contained between paired curly brackets. The assignment operator, =, associates a key with a value. Key-value pairs are separated by a semicolon. The following statement creates an associative array where the key is a name and the value is a date of birth:

$myAssocArray = @{"John Smith" = "1975/12/24"; "Alice Knowles" = "1981/03/31"}

As with standard arrays, to display the content of the associative array, you can simply type the name of the associative array:

$myAssocArray

Figure 11-23 shows the creation and display of the preceding associative array. As you can see in the figure, the each key-value pair is displayed on its own row.

Figure 11.23. Figure 11-23

Windows PowerShell is flexible over the delimiters for both the key and value—you can use single or double quotation marks to delimit the ...