Does rust need to start from the first always when getting an element by index?

help
1

For example

let a = vec![1,2,3,4,5,6,7,8,9,10];

a.get(5).unwrap(); 
a.get(0).unwrap();

Does getting the element of index-5 take more time than getting that of index 0?

Also, Is it the same when indexing tuple?

Thanks in advance.

2

Arrays are random-access data structures, so asymptotically, all elements take approximately the same time to access. (Caching can change physical access times quite a bit, but it's nevertheless usually described as O(1).)

Tuples cannot be indexed; they are simply data structures of which the fields have integer names rather than words. Accessing a tuple's fields is exactly the same operation as accessing the named fields of a struct: they are at a compile-time known constant offset, and thus also accessible in O(1).

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3

You said 'arrays', is it the same in vector?

4

In Rust Vecs and arrays have the same performance characteristics for accessing elements. A Vec is kind of just an array that can be resized dynamically.

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5

Vec is an implementation of the general concept of a dynamic array. Vec, Rust fixed-size arrays and slices are all contiguous-buffer arrays with a constant element size and have exactly the same performance characteristics when it comes to looking up elements.

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6

Thanks for your responses.