Sequence of numbers that reads the previous numbers and adds them in a list (I can’t solve this on Python)

Question

The list starts with a 0. If the last number is the first time that number appears on the list, then you add another zero. So now we have [0,0]. If the last number isn’t the first time that number appears, then you count the number of terms you’ll have to cover to reach the last time that number showed before that. So, before that second 0, there’s another, and from that second 0, to reach the first one, you go back 1 number. So the list is now [0,0,1]. The list with 6 numbers is [0,0,1,0,2,0]. I need help.

Answer 1

Ipang my bad my english was terrible…

Basically, if it isn’f the first time that a number appears on the list, you put a number that would tell you how many numbers you would have to go back to find that number

Still bad but hopefully better and sorry about it

Answer 2

I'm confused about this paragraph ...

"If the last number isn’t the first time that number appears, then you count the number of terms you’ll have to cover to reach the last time that number showed before that."

The "last time that number showed up before that" in particular, lots of "that" there ...

Answer 3

João Joana Hi! I give it a try:

https://code.sololearn.com/cSRRFxP8M93b/?ref=app

Answer 4

João Joana Hi, again!
I even made an more compact variant you can try:

def countPassedEquals(seq):
l = []
for i in range(len(seq)):
l.append(seq[:i].count(seq[i]))
return tuple(l)

https://code.sololearn.com/c2c2MDEh1Juk/?ref=app

Answer 5

Hello João Joana

Maybe not the smartest way:
seq = [0]
n = seq[-1] (n is last element)
now use a for loop to store each index where n occurs
if the length of this index list is 1 -> add 0 (the element occurs the first time)
if it is >1 -> calc last element of index list - second last element

For example:

[0,0,1,0]
n = 0
#0 is at index 0,1,3
index_list = [0,1,3]
len(index_list) > 1:
3 - 1 = 2
So you add 2 to the sequence:
[0,0,1,0,2]
n = 2
index_list = [4]
len = 1 -> add 0
[0,0,1,0,2,0]
and so on...

Answer 6

Joāo Joana,
I'm not good in English either, I just use Google translator, it's okay ...

Maybe you can show me a little example (sample list), hopefully I can understand better with that ...

It's quite an intriguing task I guess ...