27 lines
618 B
Markdown
27 lines
618 B
Markdown
---
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title: Factorial
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type: snippet
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language: python
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tags: [math,recursion]
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cover: succulent-11
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dateModified: 2020-09-15T16:13:06+03:00
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---
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Calculates the factorial of a number.
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- Use recursion.
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- If `num` is less than or equal to `1`, return `1`.
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- Otherwise, return the product of `num` and the factorial of `num - 1`.
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- Throws an exception if `num` is a negative or a floating point number.
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```py
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def factorial(num):
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if not ((num >= 0) and (num % 1 == 0)):
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raise Exception("Number can't be floating point or negative.")
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return 1 if num == 0 else num * factorial(num - 1)
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```
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```py
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factorial(6) # 720
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```
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