treyhunner, 2 months ago Today I wondered whether I could generate Fibonacci numbers in a list comprehension using #Python's walrus operator. It turns out that this is possible... and I do not recommend it. 😬🤭 >>> a = b = 1 >>> n = 15 >>> fibonacci = [(old:=a, a:=b, b:=old+b)[0] for _ in range(n)] >>> fibonacci [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]
Today I wondered whether I could generate Fibonacci numbers in a list comprehension using #Python's walrus operator.
It turns out that this is possible... and I do not recommend it. 😬🤭
>>> a = b = 1 >>> n = 15 >>> fibonacci = [(old:=a, a:=b, b:=old+b)[0] for _ in range(n)] >>> fibonacci [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]
treyhunner, 2 months ago A generator expression even works 🤯 >>> from itertools import count, islice >>> fibonacci = ((old:=a, a:=b, b:=old+b)[0] for _ in count()) >>> a = b = 1 >>> print(*islice(fibonacci, 5)) 1 1 2 3 5 Note that we defined a & b AFTER making the generator object. You can even reset a & b to start it all over: >>> a = b = 1 >>> print(*islice(fibonacci, 7)) 1 1 2 3 5 8 13 Or you could decide to switch from Fibonacci to Lucas numbers: >>> a, b = 2, 1 >>> print(*islice(fibonacci, 7)) 2 1 3 4 7 11 18
A generator expression even works 🤯
>>> from itertools import count, islice >>> fibonacci = ((old:=a, a:=b, b:=old+b)[0] for _ in count()) >>> a = b = 1 >>> print(*islice(fibonacci, 5)) 1 1 2 3 5
Note that we defined a & b AFTER making the generator object.
You can even reset a & b to start it all over:
>>> a = b = 1 >>> print(*islice(fibonacci, 7)) 1 1 2 3 5 8 13
Or you could decide to switch from Fibonacci to Lucas numbers:
>>> a, b = 2, 1 >>> print(*islice(fibonacci, 7)) 2 1 3 4 7 11 18
treyhunner, 2 months ago Yet another way, by putting an assignment expression within an assignment expression: >>> from itertools import count, islice >>> a = b = 1 >>> numbers = ((b:=a+(a:=b))-a for _ in count()) >>> list(islice(numbers, 12)) [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144] #Python #pythonoddity
Yet another way, by putting an assignment expression within an assignment expression:
>>> from itertools import count, islice >>> a = b = 1 >>> numbers = ((b:=a+(a:=b))-a for _ in count()) >>> list(islice(numbers, 12)) [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144]
#Python #pythonoddity
folkerschamel, 2 months ago @treyhunner Somebody writing such code I would first complement them for their IQ of 200 and then give them a good talking to: don't pull the hairs of your playmate. #python
@treyhunner Somebody writing such code I would first complement them for their IQ of 200 and then give them a good talking to: don't pull the hairs of your playmate. #python
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