Matching multiple patterns in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does matching multiple patterns with the | operator in Rust mean?

It means you can check if a value matches any one of several patterns in a single match arm, using the | symbol to separate patterns.

beginner

How do you write a match arm that matches the values 1, 2, or 3 in Rust?

You write:

1 | 2 | 3 => { /* code here */ }

This means if the value is 1, 2, or 3, the code runs.

intermediate

Can you bind variables when matching multiple patterns with | in Rust?

No, you cannot bind variables directly in multiple patterns combined with |. Each pattern must be independent without variable bindings.

intermediate

What happens if you try to use variable bindings in multiple patterns combined with | in Rust?

Rust will give a compile error because it cannot decide which pattern's variable to bind. You must separate those cases into different arms.

beginner

Why is matching multiple patterns useful in Rust?

It lets you write cleaner and shorter code by grouping cases that should do the same thing, avoiding repetition.

Which symbol is used to match multiple patterns in one match arm in Rust?

A |

B &

C &&

D ||

The | symbol is used to separate multiple patterns in a single match arm.

What will this Rust code print?<br>

let x = 2;<br>match x {<br>  1 | 2 | 3 => println!("Matched 1, 2, or 3"),<br>  _ => println!("No match"),<br>}

A Nothing

B No match

C Compile error

D Matched 1, 2, or 3

Since x is 2, it matches the pattern 1 | 2 | 3 and prints the first message.

Can you write this in one match arm?<br>

Some(x) => println!("Got {}", x),<br>None => println!("No value")

A Yes, using | between Some(x) and None

B Yes, by combining with &

C No, because Some(x) binds a variable and None does not

D No, because None is not a pattern

You cannot combine patterns with variable bindings and those without in one arm using |.

What error occurs if you try to bind variables in multiple patterns combined with |?

A Syntax error: unexpected token

B Cannot bind variable to multiple patterns

C Runtime panic

D No error

Rust forbids binding variables in multiple patterns combined with | because it cannot decide which binding to use.

Why use multiple patterns in one match arm?

A To handle several cases with the same code

B To improve runtime speed

C To bind variables to all patterns

D To avoid using match

It helps write cleaner code by grouping cases that share the same behavior.

Explain how to match multiple patterns in one match arm in Rust and when it is useful.

Think about grouping values that need the same action.

Describe the limitation of variable bindings when matching multiple patterns with | in Rust.

Consider why Rust cannot decide which variable to bind.