Character classes

A character class is used to match a single character to a set of possible characters. A character class is denoted using square brackets ([ ]).

For example, a character class may contain each of the vowels:

'get' -match 'g[aeiou]t' 
'got' -match 'g[aeiou]'

Within a character class, the special or reserved characters are as follows:

• -: Used to define a range
• \: Escape character
• ^: Negates the character class

Ranges

The hyphen is used to define a range of characters. For example, we might want to match any number repeated one or more times (using +):

'1st place' -match '[0-9]+'    # $matches[0] is "1" 
'23rd place' -match '[0-9]+'   # $matches[0] is "23"

A range in a character class can be any range of ASCII characters, such as the following examples:

• a-z
• A-K
• 0-9
• 1-5
• !-9 (0-9 and the ASCII characters 33 to 47)

The following returns true as " is character 34 and # is character 35 that is, they are within the range !-9:

PS> '"#' -match '[!-9]+'; $matches[0]
True
"#

The range notation allows...