Can someone give some examples for recursion function in python in addition to factorial?

Question

I understand how this recursion func works.but i don't know what are the uses.

Answer 1

It is said that you can rewrite every loop as a recursion.

Loops are usually quicker and more memory-efficient (although some languages seem to be optimized for recursion), but recursion is usually easier to read and write - if you have a firm grasp of recursion, that is. ;-)

I had a bit of trouble myself understanding and writing recursion, so I have written quite a few of recursive mini codes for practice.

Just search my codes with 'recursive' and you should get them all: max, pow, permutations etc.

Answer 2

For recursion you can find here a code that is doing flattening of lists
https://code.sololearn.com/cXmQkFaVugME/?ref=app

Answer 3

It's one of those things you rarely need until you need it.

Imagine you are writing a calculator and it has a function called `evaluate` that takes an expression like `4*(1+2+3)/8` and returns a number.
Obviously you have to do the stuff in parentheses first, and that is just another calculation.

So probably `evaluate("4*(1+2+3)/8")` will call itself recursively, like `evaluate("1+2+3")`. Then you are left with `4*6/8` which should be easy.

Through recursion your calculator can do parentheses "for free".

Answer 4

Thanks everyone.

Answer 5

Found this one from the comment section.
The one who pasted this is Werikas 7.

return 5 * factorial(4)
|
return 4 * factorial(3)
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return 3 * factorial(2)
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return 2 * factorial(1)
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return 1
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return 2 * 1
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return 3 * 2
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return 6 * 4
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return 24 * 5
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return 120

It was really helpful for me to understand what recursion is.