.entry — Used for in-place manipulation of the value for a corresponding key, scores.entry(team_id)
.or_default — Insert an empty default value if the key is not present, returning a mutable reference, scores.entry(team_id).or_default()
.or_insert — Insert a populated default value if the key is not present, also returning a mutable reference, sat_scores.entry(student_id).or_insert(400)
String slice
.len — Get the length of the string slice, name.len()
.is_empty — Check if the string slice is empty, name.is_empty()
.to_string — Convert a string slice to a String, name.to_string(); compare, contrast with String::from
Keywords
Variable Bindings and Data Declaration
let — Declare a variable
const — Declare a compile-time constant
static — Declare a static variable (global variable with a fixed memory location)
mut — Mark a binding as mutable
ref — Bind by reference
Type System
type — Create a type alias
struct — Define a structure/record type
enum — Define an enumeration type
trait — Define an interface type
impl — Implement methods or traits
dyn — Dynamic dispatch to a trait object
Self — Type alias for the implementing type within a trait or impl
self — Method receiver or current module
super — Parent module
where — Add constraints to generic types
Control Flow
if — Conditional branching
else — Alternative branch in conditional
match — Pattern matching
loop — Infinite loop
while — Conditional loop
for — Iterator-based loop
in — Part of for loop syntax and pattern matching
break — Exit a loop early
continue — Skip to the next loop iteration
return — Return from a function
Functions and Closures
fn — Define a function
move — Force closure to take ownership of captured variables
async — Define an asynchronous function or block
await — Suspend execution until an async result is ready
Memory Management
unsafe — Denote unsafe code block
extern — Link to external functions or crates
raw — Raw pointer operations (used with references)
Modules and Visibility
mod — Define a module
pub — Make an item public
use — Import items from other modules
crate — Reference the current crate or external crate