CODEWITHSUNDEEP
python
Milind Dalvi
Milind Dalvi

Reputation: 846

Fixed length sequence repeats with increments in python

Looking for a pythonic way to repeat sequences of fixed length while incrementing the sequence digits until max length is reached.

As of now, the code uses while loop and four variables one being the list itself to complete the logic as below,

l = []
i, repeat, max_len = 0, 3, 20
while True:
    if len(l) + repeat <= max_len:
        l.extend([i] * repeat)
    else:
        repeat = max_len - len(l)
        l.extend([i] * repeat)
        break
    i += 1

The above code produces

l = [0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6]

Thus, repeating a fixed length sequence of 3 units until the maximum length of 20 is reached (omit any last digits of sequence outside max_len permitted)

Is there a pythonic way of doing the same?

Upvotes: 1

Views: 406

Answers (3)

user2314737
user2314737

Reputation: 29397

With list comprehensions 

>>> i, repeat, max_len = 0, 3, 20
>>> q = max_len//repeat
>>> [x for x in range(i, i+q) for y in range(repeat)]+[i+q for y in range(max_len%repeat)]
[0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6]

With a different starting value:

>>> i = 5
>>> [x for x in range(i, i+q) for y in range(repeat)]+[i+q for y in range(max_len%repeat)]
[5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11]

Upvotes: 0

Joe Halliwell
Joe Halliwell

Reputation: 1177

How about this one:

[int(i/repeat) for i in range(max_len)]

Upvotes: 4

tyaq
tyaq

Reputation: 1

Well this will make exactly your list using list comprehension.

l = [i//(repeat) for i in range(max_len)]
# [0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6]

But I think there is a bug in the original function because there should be three 5s at the end.

l = [i//(repeat) for i in range(max_len//repeat * repeat)]
# [0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5]

Upvotes: 0

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