Pass regex options to PowerShell [regex] type

问题

I capture two groups matched using the regexp code below:

[regex]$regex = "^([0-9]{1,20})(b|kb|mb|gb|tb)$"

$matches = $regex.match($minSize)

$size=[int64]$matches.Groups[1].Value
$unit=$matches.Groups[2].Value

My problem is I want to make it case-insensitive, and I do not want to use regex modifiers.

I know you can pass regex options in .NET, but I cannot figure out how to do the same with PowerShell.

回答1:

Try using -match instead. E.g.,

$minSize = "20Gb"
$regex = "^([0-9]{1,20})(b|kb|mb|gb|tb)$"
$minSize -match $regex #Automatic $Matches variable created
$size=[int64]$Matches[1]
$unit=$Matches[2]

回答2:

Use PowerShell's -match operator instead. By default it is case-insensitive:

$minSize -match '^([0-9]{1,20})(b|kb|mb|gb|tb)$'

For case-sensitive matches, use -cmatch.

回答3:

There are overloads of the static [Regex]::Match() method that allow to provide the desired [RegexOptions] programmatically:

# You can combine several options by doing a bitwise or:
$options = [Text.RegularExpressions.RegexOptions]::IgnoreCase -bor [Text.RegularExpressions.RegexOptions]::CultureInvariant
# or by letting casting do the magic:
$options = [Text.RegularExpressions.RegexOptions]'IgnoreCase, CultureInvariant'

$match = [regex]::Match($input, $regex, $options)

回答4:

You can also include (?i) in your regex, like so (cmatch forces case sensitive match):

PS H:\> 'THISISSOMETHING' -cmatch 'something'
False
PS H:\> 'THISISSOMETHING' -cmatch '(?i)something'
True

来源：https://stackoverflow.com/questions/12977338/pass-regex-options-to-powershell-regex-type