Switch with wildcard and regex in PowerShell - Step-by-Step Execution

Concept Flow - Switch with wildcard and regex

Input value

↓

Switch statement starts

↓

Check each case

↓

Wildcard?

↓

Match?

↓

Execute case block

↓

End switch or next case

The switch statement checks the input against each case using wildcard or regex patterns, executing the matching case block.

Execution Sample

PowerShell

switch ($input) {
  "file*" { "Wildcard match: $input" }
  "regex:^data\d+$" { "Regex match: $input" }
  default { "No match" }
}

This script checks if the input matches a wildcard pattern or a regex pattern and prints the matching case.

Execution Table

Step	Input	Case Pattern	Pattern Type	Match Result	Action Taken	Output
1	file123	file*	Wildcard	Yes	Execute wildcard case	Wildcard match: file123
2	data45	file*	Wildcard	No	Check next case
3	data45	regex:^data\d+$	Regex	Yes	Execute regex case	Regex match: data45
4	test	file*	Wildcard	No	Check next case
5	test	regex:^data\d+$	Regex	No	Execute default case	No match
6	file	file*	Wildcard	Yes	Execute wildcard case	Wildcard match: file

💡 Switch ends after executing the first matching case or default if no matches.

Variable Tracker

Variable	Start	After Step 1	After Step 3	After Step 5	Final
input	N/A	file123	data45	test	file
output	N/A	Wildcard match: file123	Regex match: data45	No match	Wildcard match: file

Key Moments - 3 Insights

Why does the switch stop checking after the first match?

Because in the execution_table, once a case matches (like step 1 or 3), the switch executes that case and exits without checking further cases.

How does the switch know to treat a pattern as regex?

The pattern starting with 'regex:' tells the switch to treat the rest as a regex pattern, as shown in steps 3 and 5 in the execution_table.

What happens if no cases match?

The default case runs, as shown in step 5 where input 'test' matches no patterns, so 'No match' is output.

Visual Quiz - 3 Questions

Look at the execution_table, what output is produced at step 3?

A Regex match: data45

B Wildcard match: data45

C No match

D Wildcard match: file123

💡 Hint

Check the 'Output' column for step 3 in the execution_table.

At which step does the switch execute the default case?

A Step 1

B Step 5

C Step 3

D Step 6

💡 Hint

Look for 'Execute default case' in the 'Action Taken' column.

If the input is 'file', which case matches according to the execution_table?

A Regex case

B Default case

C Wildcard case

D No case matches

💡 Hint

See step 6 where input 'file' matches 'file*' wildcard pattern.

Concept Snapshot

switch ($input) {
  "pattern*" { action }
  "regex:pattern" { action }
  default { action }
}
- Checks cases in order
- Wildcard matches simple patterns
- regex: prefix uses regex
- Stops at first match
- default runs if no match

Full Transcript

This visual execution shows how a PowerShell switch statement uses wildcard and regex patterns to match input values. The switch checks each case in order. If the input matches a wildcard pattern like 'file*', it runs that case and stops. If not, it checks regex patterns marked with 'regex:'. If no cases match, the default case runs. The execution table traces inputs like 'file123', 'data45', and 'test' through the cases, showing which matches and what output is produced. Variables like input and output change as the switch runs. Key moments clarify why the switch stops after the first match, how regex patterns are recognized, and what happens when no match occurs. The quiz tests understanding of outputs at specific steps and case matching behavior.