The wildcard and regex parameters are used when matching strings. The wildcard parameter allows use of the characters ? (any single character) and * (any character, repeated 0 or more times) in a condition, for example:

switch -Wildcard ('cat') {
     'c*'  { Write-Host 'The word begins with c' } 
    '???' { Write-Host 'The word is 3 characters long' } 
    '*t'  { Write-Host 'The word ends with t' } 
} 

The regex parameter allows the use of regular expressions to perform comparisons (Chapter 10, Regular Expressions, will explain this syntax in greater detail), for example:

switch -Regex ('cat') {
     '^c'       { Write-Host 'The word begins with c' } 
    '[a-z]{3}' { Write-Host 'The word is 3 characters long' } 
    't$'       { Write-Host 'The word ends with t' } 
}