Other operators
PowerShell has a wide variety of operators, a few of which do not easily fall into a specific category:
- Comma: 
, - Index: 
[ ] - Range: 
.. - Call: 
& - Format: 
-f - Increment and decrement: 
++and-- - Join: 
-join NullcoalescingNullconditional- Pipeline chain
 - Background
 
Each of these operators is in common use. The range operator is often used with the index operator and arrays, the call operator can run a command based on a string, the format operator can be used to build up complex strings, and so on.
Comma
The comma operator may be used to separate elements in an array. For example:
$array = 1, 2, 3, 4
    If the comma operator is used before a single value (as a unary operator), it creates an array containing one element:
$array = ,1
    The use of unary commas is explored again in Chapter 17, Scripts, Functions, and Script Blocks.
The index operator can be used to access...