28 lines
991 B
Markdown
28 lines
991 B
Markdown
---
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title: geometric_progression
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tags: math,list,intermediate
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firstSeen: 2020-10-04T12:19:28+03:00
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lastUpdated: 2020-11-02T19:28:05+02:00
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---
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Initializes a list containing the numbers in the specified range where `start` and `end` are inclusive and the ratio between two terms is `step`.
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Returns an error if `step` equals `1`.
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- Use `range()`, `math.log()` and `math.floor()` and a list comprehension to create a list of the appropriate length, applying the step for each element.
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- Omit the second argument, `start`, to use a default value of `1`.
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- Omit the third argument, `step`, to use a default value of `2`.
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```py
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from math import floor, log
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def geometric_progression(end, start=1, step=2):
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return [start * step ** i for i in range(floor(log(end / start)
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/ log(step)) + 1)]
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```
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```py
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geometric_progression(256) # [1, 2, 4, 8, 16, 32, 64, 128, 256]
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geometric_progression(256, 3) # [3, 6, 12, 24, 48, 96, 192]
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geometric_progression(256, 1, 4) # [1, 4, 16, 64, 256]
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```
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