Strings in Rust

Last updated Dec 1, 2022 Edit Source

• Programming
• Rust

store multiple values of other types into one type.

store multiple values of any type.

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let info: (u8,f64,i32) = (1,3.3,999);
let jets = info.0;
let fuel = info.1;
let ammo = info.2;

rust uses the dot syntax to emphasize the members of tuples are not always the same type.

the second way to access a tuple is all at once

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let info = (1,3.3,999);
let (jets,fuel,ammo) = info;

tuples currently have a max airedy of 12, or the amount of items in a tuple, (you can’t have more than 12 at least with full functionality)

store multiple vals of same type

specify them literally

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let buf = [1,2,3];

or with a value in how many should be in the array with a semicolon

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let buf:[u8;3] = [1,2,3];

you index vals in array as usual with square brackets.

!! Arrays are limited to a size of 32, above witch they loose most of their functionality. Arrays live on the stack by default. so you will usually use vectors of slices of vectors instead of arrays

these get crazy, there are 6 types

but only 2 get used for most things.

1. string slice -> str, will almost always be seen as a borrowed string slice -> &str

Borrowed string slice is often refereed to as a string which is confusing because the other type is also called String with a capital S.

1. String

! Data in string slice CANNOT be modified. Data in a String CAN be modified

You will often create a string by calling the to_string() method.

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let msg = "abc".to_string();

or by using from

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let msg = String::from("abc");

A borrowed string slice is internally made up of a pointer to some bytes

&str

ptr->| a | b | c | d |

len = 4.

capacity = 8

string slices are a subset of String in more ways than one. so they share other characteristics too.

both string types are valic UTF-8

Strings CANNOT be indexed by character position. english is NOT the only language in the world

Strings are Unicode -> gets complicated

Unicode scalars in UTF-8 can be represented by 1,2,3, or 4 bytes. and you have to traverse the bytes in order.

graphemes -> scalars -> bytes

So there are some options for string stuff

using bytes.

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word.bytes(); // works well for english ASCII
word.chars(); // retrieve iterator to go through scalars

there is a package called unicode_segmentation() that can handle graphemes of many types

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graphemes(my_string,true)

There are many helper methods for strings to use but if you end up having to manually iterate through a string there is a handy function called .nth(3)