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2021-02-09 09:07:07 +00:00
< ol class = "chapter" > < li class = "chapter-item expanded " > < a href = "Chapter_0.html" > < strong aria-hidden = "true" > 1.< / strong > Update< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_1.html" > < strong aria-hidden = "true" > 2.< / strong > Introduction< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_2.html" > < strong aria-hidden = "true" > 3.< / strong > Who am I?< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_3.html" > < strong aria-hidden = "true" > 4.< / strong > Writing Rust in Easy English< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_4.html" > < strong aria-hidden = "true" > 5.< / strong > Rust Playground< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_5.html" > < strong aria-hidden = "true" > 6.< / strong > 🚧 and ⚠️< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_6.html" > < strong aria-hidden = "true" > 7.< / strong > Comments< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_7.html" > < strong aria-hidden = "true" > 8.< / strong > Types< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_8.html" > < strong aria-hidden = "true" > 9.< / strong > Type inference< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_9.html" > < strong aria-hidden = "true" > 10.< / strong > Printing 'hello, world!'< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_10.html" > < strong aria-hidden = "true" > 11.< / strong > Display and debug< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_11.html" > < strong aria-hidden = "true" > 12.< / strong > Mutability (changing)< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_12.html" > < strong aria-hidden = "true" > 13.< / strong > The stack, the heap, and pointers< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_13.html" > < strong aria-hidden = "true" > 14.< / strong > More about printing< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_14.html" > < strong aria-hidden = "true" > 15.< / strong > Strings< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_15.html" > < strong aria-hidden = "true" > 16.< / strong > const and static< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_16.html" > < strong aria-hidden = "true" > 17.< / strong > More on references< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_17.html" > < strong aria-hidden = "true" > 18.< / strong > Mutable references< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_18.html" > < strong aria-hidden = "true" > 19.< / strong > Giving references to functions< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_19.html" > < strong aria-hidden = "true" > 20.< / strong > Copy types< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_20.html" > < strong aria-hidden = "true" > 21.< / strong > Collection types< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_21.html" > < strong aria-hidden = "true" > 22.< / strong > Vectors< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_22.html" class = "active" > < strong aria-hidden = "true" > 23.< / strong > Tuples< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_23.html" > < strong aria-hidden = "true" > 24.< / strong > Control flow< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_24.html" > < strong aria-hidden = "true" > 25.< / strong > Structs< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_25.html" > < strong aria-hidden = "true" > 26.< / strong > Enums< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_26.html" > < strong aria-hidden = "true" > 27.< / strong > Loops< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_27.html" > < strong aria-hidden = "true" > 28.< / strong > Implementing structs and enums< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_28.html" > < strong aria-hidden = "true" > 29.< / strong > Destructuring< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_29.html" > < strong aria-hidden = "true" > 30.< / strong > References and the dot operator< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_30.html" > < strong aria-hidden = "true" > 31.< / strong > Generics< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_31.html" > < strong aria-hidden = "true" > 32.< / strong > Option and Result< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_32.html" >
2020-12-25 14:16:02 +00:00
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2021-02-24 06:13:19 +00:00
< h2 id = "tuples" > < a class = "header" href = "#tuples" > Tuples< / a > < / h2 >
2021-02-08 07:15:20 +00:00
< p > < strong > < a href = "https://youtu.be/U67Diy6SlTg" > See this chapter on YouTube< / a > < / strong > < / p >
2020-12-25 14:16:02 +00:00
< p > Tuples in Rust use < code > ()< / code > . We have seen many empty tuples already, because < em > nothing< / em > in a function actually means an empty tuple:< / p >
< pre > < code class = "language-text" > fn do_something() {}
< / code > < / pre >
< p > is actually short for:< / p >
< pre > < code class = "language-text" > fn do_something() -> () {}
< / code > < / pre >
< p > That function gets nothing (an empty tuple), and returns nothing (an empty tuple). So we have been using tuples a lot already. When you don't return anything in a function, you actually return an empty tuple.< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > fn just_prints() {
println!(" I am printing" ); // Adding ; means we return an empty tuple
}
fn main() {}
< / code > < / pre > < / pre >
< p > But tuples can hold many things, and can hold different types too. Items inside a tuple are also indexed with numbers 0, 1, 2, and so on. But to access them, you use a < code > .< / code > instead of a < code > []< / code > . Let's put a whole bunch of types into a single tuple.< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > fn main() {
let random_tuple = (" Here is a name" , 8, vec!['a'], 'b', [8, 9, 10], 7.7);
println!(
" Inside the tuple is: First item: {:?}
Second item: {:?}
Third item: {:?}
Fourth item: {:?}
Fifth item: {:?}
Sixth item: {:?}" ,
random_tuple.0,
random_tuple.1,
random_tuple.2,
random_tuple.3,
random_tuple.4,
random_tuple.5,
)
}
< / code > < / pre > < / pre >
< p > This prints:< / p >
< pre > < code class = "language-text" > Inside the tuple is: First item: " Here is a name"
Second item: 8
Third item: ['a']
Fourth item: 'b'
Fifth item: [8, 9, 10]
Sixth item: 7.7
< / code > < / pre >
< p > That tuple is of type < code > (& str, i32, Vec< char> , char, [i32; 3], f64)< / code > .< / p >
< p > You can use a tuple to create multiple variables. Take a look at this code:< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > fn main() {
let str_vec = vec![" one" , " two" , " three" ];
}
< / code > < / pre > < / pre >
< p > < code > str_vec< / code > has three items in it. What if we want to pull them out? That's where we can use a tuple.< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > fn main() {
let str_vec = vec![" one" , " two" , " three" ];
let (a, b, c) = (str_vec[0], str_vec[1], str_vec[2]); // call them a, b, and c
println!(" {:?}" , b);
}
< / code > < / pre > < / pre >
< p > That prints < code > " two" < / code > , which is what < code > b< / code > is. This is called < em > destructuring< / em > . That is because first the variables are inside a structure, but then we made < code > a< / code > , < code > b< / code > , and < code > c< / code > that are not inside a structure.< / p >
< p > If you need to destructure but don't want all the variables, you can use < code > _< / code > .< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > fn main() {
let str_vec = vec![" one" , " two" , " three" ];
let (_, _, variable) = (str_vec[0], str_vec[1], str_vec[2]);
}
< / code > < / pre > < / pre >
< p > Now it only creates a variable called < code > variable< / code > but doesn't make a variable for the others.< / p >
< p > There are many more collection types, and many more ways to use arrays, vecs, and tuples. We will learn more about them too, but first we will learn control flow.< / p >
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