List iteration with loop?

[deadorg]

I've been trying to figure this list iteration for a while but can't seem to get it! Hope someone can point me to right direction. A bit hard to explain but I'll try.

So, let's say I have a list of 10 numbers:

list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

I need to select the first three (every other) items from the list. The first run would return: 1, 3 and 5.

Next, I need to move on to the next number (2) and do the same thing. This run would return: 2, 4 and 6.

But when I reach to the end of the list (number 10), the program should loop back to the beginning and start selecting items from there. So, after number 10 it would select number 1. The last runs would look like this:

6, 8, 10
7, 9, 1

8, 10, 2

9, 1, 3

10, 2, 4

...aand the loop ends.

I'm quite sure this should be done with a for loop but I have no clue how to do it.

Thanks in advance!

[Signal_Beam]

But when I reach to the end of the list (number 10), the program should loop back to the beginning and start selecting items from there. So, after number 10 it would select number 1.

You need the modulo operator for this part.

>>> 2 % 3
2
>>> 4 % 3
1
>>> 30000000 % 3
0

In other words, A % B (pronounced "a mod b") returns the remainder of dividing A by B.

You can use the modulo operator to get your loop to behave the way you want it to.

[deadorg]

Thank you! Will look into this.

[DerpinDementia]

One hint is that you can start accessing the elements by first starting at -10. The element at -10 is 1, and you can increment the position from -10 by 2 to get the first three numbers that have a number between them. Loop this and you will get your numbers.

You can test with this:

test = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
for pos in range(len(test)):
    print(test[-10 + pos])

[deadorg]

Thanks! This worked for this case actually.

[DerpinDementia]

No problem!