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Arrays

An array is a collection of items stored in contiguous memory locations. It's an aggregate data structure that is designed to store a group of objects of the same type. It's the most efficient data structure for storing and accessing a sequence of objects.

How to declare an array

Create an array that holds integer values:
mut ages := [18, 25, 37]
println(ages)
Output
[18, 25, 37]
Or create an array that holds string values:
mut users := ['vbrazo', 'donnisnoni95', 'Delta456']
println(users)
Output
['vbrazo', 'donnisnoni95', 'Delta456']
Note: All elements must have the same type. The following code will not compile.
mut users := ['vbrazo', 'donnisnoni95', 'Delta456', 0]
Output
~/main.v:2:43: bad array element type `int` instead of `string`

Create an empty array

If you want to create a new empty array, just declare [] followed by the data type.
mut names := []string
mut numbers := []int

Accessing element of the array

mut users := ['vbrazo', 'donnisnoni95', 'Delta456']
println(users[0])
println(users[2])
println(users[1])
Output
vbrazo
Delta456
donnisnoni95

Append a value to an array

<< is an operator that appends a value to the end of the array.
mut ages := [18]
ages << 47
println(ages)
Output
[18, 47]
It can also append an entire array.
mut ages := [18]
ages << [47, 49]
println(ages)
Output
[18, 47, 49]

Length/size of an array

.len method returns the length of the array.
mut names := ['Thiago', 'John']
println(names.len)
Output
2

In operator

in check if an element is inside an array.
mut names := ['Thiago', 'Alex', 'Joe']
println('Vitor' in names)
println('Thiago' in names)
Output
false
true

Slicing an array

It's easy to slice an array in V. You can slice an array with the default V slicing feature without having to call the slice () method. The syntax is like this my_array[start..end]
animals := ['lion', 'goose', 'chicken', 'turkey', 'tiger']
poultry := animals[1..4]
println(poultry) // ["goose", "chicken", "turkey"]
If you want to slice from the start of the index, just ignore it to put 0 and using instead my_array[..end] or my_array[start..].
x := ['h', 'e', 'l', 'l', 'o']
y := x[..x.len-1]
z := x[1..]
println(y) // ['h', 'e', 'l', 'l']
println(z) // ['e', 'l', 'l', '0']

Exercises

  1. 1.
    Write a V program to store elements in an array and print it.
  2. 2.
    Write a V program to read n number of values in an array and display it in reverse order.
  3. 3.
    Write a V program to find the sum of all elements of the array.
  4. 4.
    Write a V program to copy the elements of one array into another array.
  5. 5.
    Write a V program to count a total number of duplicate elements in an array.
Last modified 3yr ago