A Handy Rust Cheat Sheet for Beginners

1. Variables and Data Types

• Declare a variable (immutable by default):

    let variable_name = value;
  

• Declare a mutable variable:

    let mut variable_name = value;
  

• Specify a data type:

    let variable_name: data_type = value;
  

• Common data types:

  • Integer: i32, u32, i64, u64

  • Floating-point: f32, f64

  • Boolean: bool

  • Character: char

  • String: String

  • Array: [T; N] (T: type, N: length)

  • Tuple: (T1, T2, T3) (T1, T2, T3: types)

2. Control Flow

• if statement:

    if condition {
        // code
    } else if other_condition {
        // code
    } else {
        // code
    }
  

• loop statement (infinite loop):

    loop {
        // code
    }
  

• while loop:

    while condition {
        // code
    }
  

• for loop:

    for variable in iterable {
        // code
    }
  

3. Functions

• Define a function:

    fn function_name(parameter: data_type) -> return_type {
        // code
    }
  

• Call a function:

    function_name(argument);
  

4. Enums and Pattern Matching

• Define an enum:

    enum EnumName {
        Variant1,
        Variant2,
        Variant3(data_type),
    }
  

• match statement:

    match value {
        EnumName::Variant1 => {
            // code
        },
        EnumName::Variant2 => {
            // code
        },
        EnumName::Variant3(variable) => {
            // code
        },
        _ => {
            // code
        },
    }
  

5. Error Handling

• Result enum for error handling:

    enum Result<T, E> {
        Ok(T),
        Err(E),
    }
  

• match statement with Result:

    match result {
        Ok(value) => {
            // code
        },
        Err(error) => {
            // code
        },
    }
  

• ? operator for propagating errors:

    let result = function_returning_result()?;
  

6. Collections

• Create a vector:

    let mut vector = Vec::new();
    // or
    let vector = vec![value1, value2, value3];
  

• Create a hash map:

    use std::collections::HashMap;
    let mut hash_map = HashMap::new();
  

• Create a hash set:

    use std::collections::HashSet;
    let mut hash_set = HashSet::new();
  

Detailed CheatSheet:
https://cheats.rs/