CODEWITHSUNDEEP
pythonlistrangesequence
ruby74
ruby74

Reputation: 147

Defining the length of sequence instead of the step size

I am new to python and want a function which produces a list that contains a number of integers i.e. [1,3,5,7....] like you can do with the range function i.e. range(1,21,2).

However instead of setting the upper limit I want to set how long the list should be, so I would state the starting point, the step and the number of integers I want in my list. Does such a function exist?

Upvotes: 2

Views: 3513

Answers (2)

Martijn Pieters
Martijn Pieters

Reputation: 1121724

No, but it's pretty easy to make one:

def myrange(start, step, count):
    return range(start, start + (step * count), step)

short demonstration:

>>> myrange(10, 2, 5)
[10, 12, 14, 16, 18]
>>> myrange(10, -2, 5)
[10, 8, 6, 4, 2]

In python 3 it'll return a range object, just like the regular range() function would:

>>> myrange(10, 2, 5)
range(10, 20, 2)
>>> list(myrange(10, 2, 5))
[10, 12, 14, 16, 18]

Upvotes: 7

unutbu
unutbu

Reputation: 879421

Martijn Pieter's answer is good for integers. If start orstep may be floats, you could use a list comprehension:

[start+i*step for i in range(count)]

Upvotes: 5

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