#### Iterating over array elements

When working with arrays, you usually have to work with all the elements of the array at once.

**Iterate through elements**: loop through all the elements of the array and, if necessary, perform some operation on each of them.

For this, a loop with a variable is most often used, which changes from

`0`

to

`N-1`

, where

`N`

is the number of array elements.

Under

`N`

we will consider the current size of the array, i.e.

`N = len(A)`.

...
for i in range(N):
# here we work with A[i]
...
In the specified loop, the variable `i`

will take the values `0, 1, 2, ..., N-1`. Thus, at each step of the loop, we access a specific element of the array with the number `i`

.

Thus, it is enough to describe what needs to be done with one element of the `A[i]`

array and place these actions inside such a loop.

Let's write a program that fills the array with the first `N`

natural numbers, that is, at the end of the program, the elements of the array should become equal
A[0] = 1
A[1] = 2
A[2] = 3
...
A[N - 1] = N
It is easy to see the pattern: the value of an array element must be greater by 1 than the index of the element.

The loop will look like this
for i in range(N):
A[i] = i + 1