Rust Ultimate Cheathseet
Atharva Pandey14 min read
This is “The Only Cheatsheet You Will Ever Need for Rust”. I’ve got to be upfront with you — keeping track of syntax while juggling multiple programming languages can really mess with my head. Sometimes, I’m coding away, and I find myself wishing I remembered that one killer feature or trick. Or, even worse, I look back at my code and kick myself for not optimizing it with some slick Rust feature I totally forgot about. That’s exactly why I decided to put together this exhaustive cheatsheet. It’s for folks like me who want to dive deep into Rust’s powerful features without getting bogged down by the constant “What was that syntax again?” moments.
Vector & Linked List Operations
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|----------------|---------------|-----------------|------------------|---------------------------------------------------------------|
| `Vec<T>` | `new()` | O(1) | O(1) | Creates a new empty vector. |
| | `push(value)` | Amortized O(1) | O(1) | Adds an element to the end of the vector. |
| | `pop()` | O(1) | O(1) | Removes the last element from the vector and returns it. |
| | `get(index)` | O(1) | O(1) | Returns a reference to the element at the specified index. |
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|-------------------|--------------------|---------------------|---------------------|---------------------------------------------------------------|
| `VecDeque<T>` | `new()` | O(1) | O(1) | Creates a new empty double-ended queue. |
| | `push_front(value)`| Amortized O(1) | O(1) | Inserts an element at the front of the deque. |
| | `push_back(value)` | Amortized O(1) | O(1) | Inserts an element at the back of the deque. |
| | `pop_front()` | O(1) | O(1) | Removes and returns the first element of the deque. |
| | `pop_back()` | O(1) | O(1) | Removes and returns the last element of the deque. |
| `LinkedList<T>` | `new()` | O(1) | O(1) | Creates a new empty linked list. |
| | `push_front(value)`| O(1) | O(1) | Inserts an element at the beginning of the list. |
| | `push_back(value)` | O(1) | O(1) | Inserts an element at the end of the list. |
| | `pop_front()` | O(1) | O(1) | Removes and returns the first element of the list. |
| | `pop_back()` | O(1) | O(1) | Removes and returns the last element of the list. |
HashMap Operations
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|----------------|---------------|-----------------|------------------|---------------------------------------------------------------|
| `HashMap<K,V>` | `new()` | O(1) | O(1) | Creates a new empty hash map. |
| | `insert(k,v)` | Average O(1) | O(1) | Inserts a key-value pair into the map. |
| | `get(&k)` | Average O(1) | O(1) | Returns a reference to the value corresponding to the key. |
| | `remove(&k)` | Average O(1) | O(1) | Removes a key from the map and returns its value. |
HashSet Operations
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|----------------|-------------------|-----------------|------------------|---------------------------------------------------------------|
| `HashSet<T>` | `new()` | O(1) | O(1) | Creates a new empty hash set. |
| | `insert(value)` | Average O(1) | O(1) | Adds a value to the set. |
| | `contains(&value)`| Average O(1) | O(1) | Checks if the set contains a value. |
| | `remove(&value)` | Average O(1) | O(1) | Removes a value from the set. |
String Operations
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|----------------|-----------------|-------------------|-------------------|------------------------------------------------------------------|
| `String` | `new()` | O(1) | O(1) | Creates a new empty string. |
| | `push_str(s)` | Amortized O(1) | O(1) | Appends a string slice to the end of the string. |
| | `pop()` | O(1) | O(1) | Removes the last character from the string and returns it. |
| | `trim()` | O(n) | O(1) | Returns a string slice with leading and trailing whitespace removed. |
| | `split(delimiter)` | O(n) | O(1) | Returns an iterator over substrings of the string, split by the given delimiter. |
Iterator Operations
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|----------------|----------------|-------------------|-------------------|------------------------------------------------------------------|
| Iterators | `map(f)` | Lazy | O(1) | Applies function `f` to each element of the iterator. |
| | `filter(p)` | Lazy | O(1) | Filters elements of the iterator based on predicate `p`. |
| | `fold(init, f)`| O(n) | O(1) | Reduces the iterator to a single value using the initial value and function `f`. |
| | `collect()` | O(n) | O(n) | Transforms the iterator into a collection. |
| | `zip(it)` | Lazy | O(1) | Zips two iterators into a single iterator of pairs. |
| | `chain(it)` | Lazy | O(1) | Chains two iterators together into a single iterator. |
Advanced Iterator Methods
| Data Structure / Trait | Method | Time Complexity | Space Complexity | Description |
|-------------------------|-------------------------------|-----------------|------------------|------------------------------------------------------------------|
| Iterators | `take(n)` | O(1) | O(1) | Creates an iterator that yields its first `n` elements. |
| | `skip(n)` | O(1) | O(1) | Creates an iterator that skips the first `n` elements. |
| | `enumerate()` | O(1) | O(1) | Adds a counter to each item of the iterator. |
| | `peekable()` | O(1) | O(1) | Converts the iterator into a peekable iterator. |
| | `filter_map(f)` | O(n) | O(1) | Filters and maps the iterator by a function `f`. |
Binary Heap Operations
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|-------------------|------------------|-----------------|------------------|------------------------------------------------------------------|
| `BinaryHeap<T>` | `new()` | O(1) | O(1) | Creates a new empty binary heap. |
| | `push(value)` | O(log n) | O(1) | Adds an element to the binary heap. |
| | `pop()` | O(log n) | O(1) | Removes and returns the maximum element of the heap. |
| | `peek()` | O(1) | O(1) | Returns a reference to the maximum element of the heap. |
B-Tree Map Operations
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|----------------|------------------|-----------------|------------------|------------------------------------------------------------------|
| `BTreeMap<K, V>`| `new()` | O(1) | O(1) | Creates a new empty B-tree map. |
| | `insert(key, value)` | O(log n) | O(1) | Inserts a key-value pair into the map, maintaining order. |
| | `get(&key)` | O(log n) | O(1) | Returns a reference to the value corresponding to the key. |
| | `remove(&key)` | O(log n) | O(1) | Removes a key from the map, maintaining order. |
B-Tree Set Operations
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|----------------|-----------------|-----------------|------------------|-----------------------------------------------------------------|
| `BTreeSet<T>` | `new()` | O(1) | O(1) | Creates a new empty B-tree set. |
| | `insert(value)` | O(log n) | O(1) | Adds a value to the set, maintaining order. |
| | `contains(&value)` | O(log n) | O(1) | Checks if the set contains a value. |
| | `remove(&value)`| O(log n) | O(1) | Removes a value from the set, maintaining order. |
Option and Result Types
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|----------------|-----------------|-----------------|------------------|------------------------------------------------------------------|
| `Option<T>` | `is_some()` | O(1) | O(1) | Returns `true` if the option is a `Some` value. |
| | `is_none()` | O(1) | O(1) | Returns `true` if the option is a `None` value. |
| | `unwrap()` | O(1) | O(1) | Unwraps an option, yielding the content of a `Some`. |
| | `unwrap_or(def)`| O(1) | O(1) | Returns the contained value or a default. |
| `Result<T, E>` | `is_ok()` | O(1) | O(1) | Returns `true` if the result is an `Ok` value. |
| | `is_err()` | O(1) | O(1) | Returns `true` if the result is an `Err` value. |
| | `unwrap()` | O(1) | O(1) | Unwraps a result, yielding the content of an `Ok`. |
| | `unwrap_or(def)`| O(1) | O(1) | Returns the contained `Ok` value or a default. |
File and I/O Operations
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|----------------|-----------------|---------------------|-------------------|------------------------------------------------------------------|
| `File` | `open(path)` | O(1)* | O(1) | Opens a file in read-only mode. |
| | `create(path)` | O(1)* | O(1) | Creates a new file, truncating it if it already exists. |
| | `read(&mut buf)`| O(n)* | O(1) | Reads bytes from the file into the buffer. |
| | `write(&buf)` | O(n)* | O(1) | Writes the buffer's bytes to the file. |
| `BufReader` | `new(reader)` | O(1) | O(1) | Wraps a reader and provides buffering for it. |
| `BufWriter` | `new(writer)` | O(1) | O(1) | Wraps a writer and provides buffering for it. |
File System Operations
| Data Structure / Trait | Method | Time Complexity | Space Complexity | Description |
|-------------------------|-----------------------------------|-----------------|------------------|------------------------------------------------------------------|
| `std::fs::File` | `create(path)` | O(1)* | O(1) | Creates a new file or truncates an existing file. |
| `std::fs::DirBuilder` | `new()` | O(1) | O(1) | Creates a new `DirBuilder`. |
| | `create(path)` | O(1)* | O(1) | Creates a directory at the specified path. |
| `std::fs` | `read_dir(path)` | O(1)* | O(1) | Reads the contents of a directory. |
| | `remove_file(path)` | O(1)* | O(1) | Removes a file at the specified path. |
| | `copy(source, destination)` | O(n)* | O(1) | Copies a file from source to destination. |
Concurrency Primitives
| Data Structure | Method | Time Complexity | Space Complexity | Description |
|--------------------|---------------------|-----------------|------------------|------------------------------------------------------------------|
| `Thread` | `spawn(f)` | O(1) | O(1) | Creates a new thread of execution. |
| `Mutex<T>` | `lock()` | O(1) | O(1) | Locks the mutex, blocking the current thread until it is available. |
| `Arc<T>` | `new(data)` | O(1) | O(1) | Creates a new atomic reference-counted pointer. |
| `mpsc::Sender<T>` | `send(value)` | O(1) | O(1) | Sends a value to the corresponding receiver. |
| `mpsc::Receiver<T>`| `recv()` | O(1) | O(1) | Blocks the current thread until a value is received. |
| `std::sync::atomic` | Atomic operations | O(1) | O(1) | Provides primitive shared-memory communication between threads. |
| `std::sync::Barrier` | `Barrier::new(n)` | O(1) | O(1) | Enables multiple threads to synchronize the beginning of some computation. |
Asynchronous Programming
| Data Structure / Trait | Method | Time Complexity | Space Complexity | Description |
|-------------------------|-------------------------------|-----------------|------------------|------------------------------------------------------------------|
| `std::future::Future` | `await` | O(1) | O(1) | Awaits the completion of an asynchronous operation. |
| `std::task::Poll` | Used in `Future::poll` | O(1) | O(1) | Enum used to represent the return value of `Future::poll`. |
Advanced Numerics and Math Operations
| Data Structure / Trait | Method | Time Complexity | Space Complexity | Description |
|------------------------|-----------------------|-----------------|------------------|-------------------------------------------------------------------|
| `std::cmp::Ord` | `cmp(&self, other)` | O(1) | O(1) | Compares two values and returns an ordering. |
| `std::iter::Sum` | `sum<I: Iterator>` | O(n) | O(1) | Sums up all items in the iterator. |
| `std::iter::Product` | `product<I: Iterator>`| O(n) | O(1) | Multiplies all items in the iterator. |
Traits and Pattern Matching
| Trait / Feature | Method / Use Case | Time Complexity | Space Complexity | Description |
|-----------------------|-------------------------|-----------------|------------------|--------------------------------------------------------------------|
| `std::fmt::Debug` | `{:?}` (formatting) | O(n) | O(1) | Formats a value using its debug representation. |
| `std::fmt::Display` | `{}` (formatting) | O(n) | O(1) | Formats a value using its display representation. |
| Pattern Matching | `match val {}` | O(1) - O(n) | O(1) | Matches values against patterns and deconstructs them. |
| Enums and Matching | `enum {Variants}` | O(1) | O(1) | Defines an enumeration and matches its variants in control flows. |
Traits for Generic Programming
| Trait | Method / Associated Function | Time Complexity | Space Complexity | Description |
|-----------------------------|---------------------------------|-----------------|------------------|------------------------------------------------------------------|
| `std::iter::Iterator` | `next()` | O(1) | O(1) | Advances the iterator and returns the next value. |
| `std::convert::From` | `from()` | O(1) | O(1) | Converts a value from one type to another. |
| `std::convert::Into` | `into()` | O(1) | O(1) | Consumes the original value, returning the converted value. |
| `std::default::Default` | `default()` | O(1) | O(1) | Provides a default value for a type. |
| `std::clone::Clone` | `clone()` | O(n) | O(n) | Creates a new instance of a type by cloning its content. |
| `std::cmp::PartialEq` | `eq(&self, other)` | O(1)-O(n) | O(1) | Provides functionality for partial equality comparisons. |
Advanced Pattern Matching and Enums
| Feature | Use Case | Time Complexity | Space Complexity | Description |
|--------------------------|----------------------------------|-----------------|------------------|------------------------------------------------------------------|
| Enums with `match` | `match enum_var { ... }` | O(1) | O(1) | Deconstructs enums in a type-safe way with pattern matching. |
| Pattern Guards | `if let Some(x) = expr { ... }` | O(1) | O(1) | Combines pattern matching with conditional guards. |
| `@` Bindings | `match val { pat @ subpat => ...}`| O(1) | O(1) | Allows binding a name to a value tested by a deeper pattern. |
Collections and Their Advanced Uses
| Data Structure / Trait | Method | Time Complexity | Space Complexity | Description |
|------------------------|--------------------------|---------------------|------------------|------------------------------------------------------------------|
| `std::collections::Range` | `start..end` | O(1) | O(1) | Represents an iterator over a range of values. |
| `std::slice::Slice` | `binary_search(&self)` | O(log n) | O(1) | Searches for an element in a sorted slice using binary search. |
| `std::vec::Vec` | `resize_with(len, f)` | O(n) | O(n) | Resizes the vector to the new length with a function to create elements. |
Error Handling and Debugging
| Feature / Trait | Method / Use Case | Time Complexity | Space Complexity | Description |
|-----------------------|-------------------------|-----------------|------------------|------------------------------------------------------------------|
| `std::result::Result` | `map_err(f)` | O(1) | O(1) | Maps a `Result<T, E>` to `Result<T, F>` by applying a function to a contained `Err` value. |
| `std::option::Option` | `and_then(f)` | O(1) | O(1) | Calls a function on the contained value of an `Option` or returns `None`. |
| `std::panic` | `panic!("msg")` | O(1) | O(1) | Triggers a panic with a custom message. |
| `std::dbg!` | `dbg!(&val)` | O(n) | O(1) | Prints and returns the value of a given expression for quick debugging. |
| `std::error::Error` | `description()` | O(1) | O(1) | Provides a description of the error. |
| `std::panic::catch_unwind(f)` | Try to catch panics within `f` | O(1) | O(1) | Allows potentially recovering from panics within a given function. |
Time Operations
| Data Structure / Trait | Method | Time Complexity | Space Complexity | Description |
|-------------------------|-------------------------------|-----------------|------------------|------------------------------------------------------------------|
| `std::time::Instant` | `now()` | O(1) | O(1) | Returns an instance of `Instant` representing the current moment.|
| | `duration_since(other)` | O(1) | O(1) | Calculates the duration since a previous instant. |
| `std::time::Duration` | `from_secs(secs)` | O(1) | O(1) | Creates a new `Duration` from a specified number of seconds. |
| | `as_secs()` | O(1) | O(1) | Returns the total number of seconds contained by this duration. |
Networking
| Data Structure / Trait | Method | Time Complexity | Space Complexity | Description |
|-------------------------|-------------------------------|-----------------|------------------|------------------------------------------------------------------|
| `std::net::TcpListener` | `bind(addr)` | O(1)* | O(1) | Binds to the specified address and returns a TCP listener. |
| `std::net::TcpStream` | `connect(addr)` | O(1)* | O(1) | Connects to a TCP listener at the specified address. |
| | `read(&mut buf)` | O(n)* | O(1) | Reads data from the TCP stream into the buffer. |
| | `write(&buf)` | O(n)* | O(1) | Writes data from the buffer to the TCP stream. |
Meta-programming and Macros
| Feature / Trait | Use Case | Time Complexity | Space Complexity | Description |
|----------------------------|-----------------------------------|-----------------|------------------|------------------------------------------------------------------|
| Macros | `macro_rules! macro_name {...}` | Compile-time | - | Allows writing code that generates other code (metaprogramming). |
| `std::marker::PhantomData` | Used in generic types | - | O(1) | Allows indicating phantom type parameters which affect type variance. |
| Declarative Macros | `macro_rules!` | Compile-time | - | Allows writing DRY code with pattern matching on macro arguments.|
| Procedural Macros | Custom derive, `#[proc_macro]` | Compile-time | - | More flexible macros that operate on the Rust AST for custom traits or attribute-like macros.|
| Attribute Macros | `#[attribute_macro]` | Compile-time | - | Macros that are applied to modules, functions, or structs to generate or modify code.|
| `std::macro` | `concat!`, `env!`, `cfg!` | Compile-time | - | Built-in macros for concatenating literals, accessing environment variables, and conditional compilation. |
Unsafe Operations
| Feature | Use Case | Time Complexity | Space Complexity | Description |
|--------------------------|------------------------------------|-----------------|------------------|------------------------------------------------------------------|
| `unsafe` blocks | `unsafe { ... }` | - | - | Performs operations that the compiler can't guarantee to be safe.|
| `std::ptr` | `null()`, `is_null()`, `read()`, `write()` | - | - | Provides raw pointer functionality, such as dereferencing or arithmetic. |
Conclusion
And there you have it — we’ve made it through “Rust Ultimate: The Only Cheatsheet You Will Ever Need for Rust.” From the basics to the nitty-gritty advanced stuff, I’ve poured what I know and what I’ve learned about Rust into this guide. It’s been quite the journey, filled with aha moments and a fair share of head-scratchers. But here’s the thing — Rust is an ever-evolving language, backed by an incredibly innovative and welcoming community. This cheatsheet is a solid starting point, but the real magic happens when you start applying what you’ve learned, contribute to the community, and maybe even build something awesome along the way. Keep experimenting, keep learning, and let’s keep making our Rust journey an exciting adventure. Happy coding, and let’s write some blazing-fast, memory-safe code together!
Note:
Please feel free to suggest any additions to this cheatsheet. I’m keen on updating it regularly to ensure it remains comprehensive and up-to-date. If there’s anything you think I might have missed or if there are new Rust features and best practices worth including, I’d love to hear about them. Your input will help make this resource even better for everyone in our Rust journey.
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