Rust by Example

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More Vec methods can be found under the std::vec module

Strings

There are two types of strings in Rust: String and &str.

A String is stored as a vector of bytes (Vec), but guaranteed to always be a valid UTF-8 sequence. String is heap allocated, growable and not null terminated.

&str is a slice (&[u8]) that always points to a valid UTF-8 sequence, and can be used to view into a String, just like &[T] is a view into Vec.

fn main() {

// (all the type annotations are superfluous)

// A reference to a string allocated in read only memory

let pangram: &'static str = "the quick brown fox jumps over the lazy dog";

println!("Pangram: {}", pangram);

// Iterate over words in reverse, no new string is allocated

println!("Words in reverse");

for word in pangram.split_whitespace().rev() {

println!("> {}", word);

}

// Copy chars into a vector, sort and remove duplicates

let mut chars: Vec = pangram.chars().collect();

chars.sort();

chars.dedup();

// Create an empty and growable `String`

let mut string = String::new();

for c in chars {

// Insert a char at the end of string

string.push(c);

// Insert a string at the end of string

string.push_str(", ");

}

// The trimmed string is a slice to the original string, hence no new

// allocation is performed

let chars_to_trim: &[char] = &[' ', ','];

let trimmed_str: &str = string.trim_matches(chars_to_trim);

println!("Used characters: {}", trimmed_str);

// Heap allocate a string

let alice = String::from("I like dogs");

// Allocate new memory and store the modified string there

let bob: String = alice.replace("dog", "cat");

println!("Alice says: {}", alice);

println!("Bob says: {}", bob);

}

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