Go vs Rust - Array and Vector (Rust)

 Array

programming languages. In the program, sometimes we need to store a collection of data of the same type, like a list of student marks. Such type of collection is stored in a program using an Array. 

Go

An array is a fixed-length sequence that is used to store homogeneous elements in the memory. Due to their fixed length array are not much popular like Slice in Go language. In Go language, an array is of value type not of reference type. So when the array is assigned to a new variable, then the changes made in the new variable do not affect the original array.

// Creating an array of string type Using var keyword
var myarr[3]string
// Elements are assigned using index
myarr[0] = "GFG"
myarr[1] = "GeeksforGeeks"
myarr[2] = "Geek"

Using shorthand declaration

// Shorthand declaration of array
arr:= [4]string{"geek", "gfg", "Geeks1231", "GeeksforGeeks"}

fmt.Println("Length of the array 1 is:", len(arr))

// Creating an array whose size is determined 
// by the number of elements present in it
// Using ellipsis
myarray:= [...]string{"GFG", "gfg", "geeks",
                    "GeeksforGeeks", "GEEK"}

Multi-Dimensional Array

Multi-Dimensional arrays are the arrays of arrays of the same type. 

// Creating and initializing 2-dimensional array
// Using shorthand declaration
// Here the (,) Comma is necessary
arr:= [3][3]string{{"C#", "C", "Python"}, 
                   {"Java", "Scala", "Perl"},
                    {"C++", "Go", "HTML"},}

Rust

An Array in Rust programming is a fixed-sized collection of elements denoted by [T; N] where is T is the element type and N is the compile-time constant size of the array.

We can create an array in 2 different ways:

• Simply a list with each element [a, b, c].
• Repeat expression [N, X].  This will create an array with N copies of X.

let mut array: [i32; 5] = [0; 5];
array[1] = 1;
array[2] = 2;
array[3] = 3;
array[4] = 4;
assert_eq!([1, 2 , 3 ,4], &array[1..]);
let arr = [1,2,3,4,5];
println!("array size is :{}",arr.len());
for index in 0..5 {
    println!("index is: {} & value is : {}",index, arr[index]);
}

Multi Array

use std::ops::{Index, Range};
struct ArrayView<'arr> {
    data: &'arr [[usize; 50]; 50],
    offsets: [usize; 2],
    size: [usize; 2],
}

Vector in Rust

Vector is a module in Rust that provides the container space to store values. It is a contiguous resizable array type, with heap-allocated contents.It can be increase size dynamically during runtime.Its length defines the number of elements present in the vector. Its capacity defines the actual allocated space on the heap of this vector that is in the form of 2^n.

let v : Vec<i64> = Vec::new(); 

or

let v = vec!['G','E','E','K','S'];

Examples

    // here index is the non negative value which is smaller than the size of the vector
    let index: usize = 3;
 
    let ch: char = v[index];
    let ch: Option<&char> = v.get(index);
    //loop to iterate elements in vector
    for i in v 
    { 
        // iterating through i on the the vector
        print!("{} ",i); 
    } 
    v.push('A');
    v.push('B');
    v.push('C');