rust-ape-example/src/bin/std_str.rs
2022-09-07 10:49:49 +05:30

69 lines
2.1 KiB
Rust

// ./src/std/str.md
fn part0() {
// (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<char> = 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);
}
fn part1() {
// You can use escapes to write bytes by their hexadecimal values...
let byte_escape = "I'm writing \x52\x75\x73\x74!";
println!("What are you doing\x3F (\\x3F means ?) {}", byte_escape);
// ...or Unicode code points.
let unicode_codepoint = "\u{211D}";
let character_name = "\"DOUBLE-STRUCK CAPITAL R\"";
println!("Unicode character {} (U+211D) is called {}",
unicode_codepoint, character_name );
let long_string = "String literals
can span multiple lines.
The linebreak and indentation here ->\
<- can be escaped too!";
println!("{}", long_string);
}
pub fn main() {
part0();
part1();
}