La Fée Verte @Absinthe@qoto.org
The green faerie
Joined Aug 2019
re: A Python solution
@billstclair @zingbretsen Hey bill please remember to include #toyprogrammingchallenge hashtag in your responses so people can find them by searching for it.
Can I run this in gcl or emacs or do I need more code to have the list and output?
A Python solution
@zingbretsen am pretty sure there is no technical reason not to use division, just to make the problem more complicated. I am getting ready to put up a new one. But feel free to keep playing with this one. I got a new one today, but it seems a little "specific" because they give a python code starting point, and want you to serialize and deserialize a binary tree. I will likely not put that one up as a freebie. Especially since I want to get the new real on up.
A Python solution
@zingbretsen This works...
print("One Liner no division")
print([reduce(lambda a, b: a *b,
[ y for x, y in enumerate(random_list) if x != idx])
for idx, _ in enumerate(random_list)])
It's a one liner, except I am sticking to 80 columns so I split it a few times.. still calling it a one liner :)
A Python solution
@zingbretsen What about this... as a one liner:
[reduce(lambda a, b: a *b, [ y for x, y in enumerate(list) if x != idx]) for idx, _ in enumerate(list)]
A Python solution
@zingbretsen right... bbiab, errand time
A Python solution
@zingbretsen The only problem I have with all of these no-division solutions is that you have to do the multiplication in all cases. I wonder if there is a mathematical trick to somehow solve without having to calculate the whole product each time, like the division solution. @freemo ... any ideas?
@zingbretsen sounds like the big data functions. :)
@zingbretsen yeah, I looked it up. Works nice, perhaps I will try it with the list comprehension that I suggested.
A Python solution
@zingbretsen Okay, this is less of a criticism as it is a question of understanding:
You used the deque to rotate and slice the list for the multiplication, Could you have also used list comprehension something like this:
current_index = the one we are working on
[ value for idx, value in enumerate(list) if idx != current_idx]
I know you wanted to use the deque
A Python solution
@zingbretsen now you are stretching me. I have never seen rotate() but I can intuit what it does. I also have not used lamda's. But what is happening in the reduce() call? I assume the lamda takes 2 values how is that acting on the list? Or is the lamda being passed into the reduce call ... time to read about reduce :)
La Fée Verte
boosted
A Python solution
@Absinthe Here is my #toyprogrammingchallenge no-division solution:
```
#!/usr/bin/env python
from collections import deque
from functools import reduce
from random import randint
def get_product_and_rotate(d):
"""Gets product of all but the first items in the queue"""
prod = reduce(lambda a, b: a * b, list(d)[1:])
d.rotate(-1) # Rotates left so that the next
return prod
if __name__ == "__main__":
n_items = randint(2, 10)
input_list = [randint(0, 9) for _ in range(n_items)]
print(input_list)
product_queue = deque(input_list)
print([get_product_and_rotate(product_queue) for _ in input_list])
```
Uses `reduce` for the multiplication, and uses a `deque` (double-ended queue) to rotate the list. I've read that using a deque is actually more efficient than just taking slices out of the list.
@namark I have not had a chance to try to compile mercury yet. I don't do much with procedural languages. I guess there is no time like the present.
@namark Thanks! It still doesn't feel intuitive yet. If I came across such a line I would have to work it out to see what it did. But hey, it does work and with all the corner cases I could think of.
@pry@niu.moe use whatever language you like.
@pry@niu.moe
If you click the hashtag it should take you to all conversations about it.
Basically I am proposing small programming problems/puzzles. People can try them or evaluate the work of others' attempts. Or however you feel you will get something out of it?
Here should be a link to the beginning:
@namark
This has now been fixed.
@serra jump right in. Just remember to include the hash tag #toyprogrammingchallenge
@selontheweb
((____))
(o. o)
(@)
@serra it can be. But TDD is about development rather than testing.
On another note have you participated the in my #toyprogrammingchallenge ?
