2022-03-02 06:57:13 -06:00
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1.
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```rust
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fn main() {
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let s: &str = "hello, world";
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}
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```
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2.
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```rust
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fn main() {
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let s: Box<str> = "hello, world".into();
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greetings(&s)
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}
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fn greetings(s: &str) {
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println!("{}",s)
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}
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```
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2022-03-15 19:22:24 -06:00
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```rust
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fn main() {
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let s: Box<&str> = "hello, world".into();
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greetings(*s)
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}
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fn greetings(s: &str) {
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println!("{}", s);
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}
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```
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2022-03-02 06:57:13 -06:00
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3.
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```rust
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fn main() {
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let mut s = String::new();
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s.push_str("hello, world");
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s.push('!');
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assert_eq!(s, "hello, world!");
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}
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```
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4.
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```rust
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fn main() {
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let mut s = String::from("hello");
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s.push(',');
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s.push_str(" world");
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s += "!";
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println!("{}", s)
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}
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```
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5.
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```rust
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fn main() {
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let s = String::from("I like dogs");
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// Allocate new memory and store the modified string there
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let s1 = s.replace("dogs", "cats");
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assert_eq!(s1, "I like cats")
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}
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```
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6.
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```rust
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fn main() {
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let s1 = String::from("hello,");
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let s2 = String::from("world!");
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let s3 = s1.clone() + &s2;
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assert_eq!(s3,"hello,world!");
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println!("{}",s1);
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}
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```
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7.
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```rust
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fn main() {
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let s = "hello, world".to_string();
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greetings(s)
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}
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fn greetings(s: String) {
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println!("{}",s)
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}
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```
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```rust
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fn main() {
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let s = String::from("hello, world");
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greetings(s)
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}
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fn greetings(s: String) {
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println!("{}",s)
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}
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```
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8.
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```rust
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fn main() {
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let s = "hello, world".to_string();
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let s1: &str = &s;
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}
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```
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```rust
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fn main() {
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let s = "hello, world";
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let s1: &str = s;
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}
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```
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```rust
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fn main() {
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let s = "hello, world".to_string();
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let s1: String = s;
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}
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```
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9.
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```rust
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fn main() {
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// You can use escapes to write bytes by their hexadecimal values
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// fill the blank below to show "I'm writing Rust"
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let byte_escape = "I'm writing Ru\x73\x74!";
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println!("What are you doing\x3F (\\x3F means ?) {}", byte_escape);
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// ...or Unicode code points.
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let unicode_codepoint = "\u{211D}";
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let character_name = "\"DOUBLE-STRUCK CAPITAL R\"";
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println!("Unicode character {} (U+211D) is called {}",
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unicode_codepoint, character_name );
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let long_string = "String literals
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can span multiple lines.
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The linebreak and indentation here \
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can be escaped too!";
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println!("{}", long_string);
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}
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```
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10.
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```rust
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fn main() {
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let raw_str = "Escapes don't work here: \x3F \u{211D}";
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// modify below line to make it work
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assert_eq!(raw_str, "Escapes don't work here: ? ℝ");
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// If you need quotes in a raw string, add a pair of #s
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let quotes = r#"And then I said: "There is no escape!""#;
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println!("{}", quotes);
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// If you need "# in your string, just use more #s in the delimiter.
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// You can use up to 65535 #s.
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let delimiter = r###"A string with "# in it. And even "##!"###;
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println!("{}", delimiter);
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// fill the blank
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let long_delimiter = r###"Hello, "##""###;
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assert_eq!(long_delimiter, "Hello, \"##\"")
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}
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```
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11.
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```rust
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fn main() {
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let s1 = String::from("hi,中国");
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let h = &s1[0..1];
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assert_eq!(h, "h");
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let h1 = &s1[3..6];
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assert_eq!(h1, "中");
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}
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```
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12.
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```rust
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fn main() {
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for c in "你好,世界".chars() {
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println!("{}", c)
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}
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}
|
2022-03-15 19:22:24 -06:00
|
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```
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