Linked Questions
10 questions linked to/from How does reduce function work?
22
votes
3
answers
33k
views
Reduce function with three parameters [duplicate]
How does reduce function work in python3 with three parameters instead of two.
So, for two,
tup = (1,2,3)
reduce(lambda x, y: x+y, tup)
I get this one. This would just sum up all the elements in tup. ...
- 915
0
votes
5
answers
751
views
python reduce function returns false for check same element in a list [duplicate]
>>> reduce(lambda x,y: x == y, [2,2,2,2,2])
False
I want to check every element in a list if they are the same and I thought this would do the trick, apprarently not. Can you some explain why ...
user11528729
8
votes
6
answers
3k
views
Is it possible to sort a list with reduce?
I was given this as an exercise. I could of course sort a list by using sorted() or other ways from Python Standard Library, but I can't in this case. I think I'm only supposed to use reduce().
from ...
- 5,446
8
votes
5
answers
3k
views
Create dynamic level nested dict from a list of objects?
I am trying to turn a list of objects into a nested dict which could be accessed by indexes.
The following code works for a two-level nested dictionary. I would like to extend it to work flexibly for ...
- 7,582
2
votes
4
answers
299
views
behaviour of reduce function in python
I am confused by the behavior of the reduce function.
In the first example, I get the expected result: (1-1/2) * (1-1/3) = 1/3
>>> reduce(lambda x, y: (1 - 1.0/x) * (1 - 1.0/y), [2,3])
0....
- 634
2
votes
3
answers
3k
views
creating cumulative percentage from a dictionary of data
Given a dictionary (or Counter) of tally data like the following:
d={'dan':7, 'mike':2, 'john':3}
and a new dictionary "d_cump" that I want to contain cumulative percentages
d_cump={'mike':16, 'john'...
- 23
1
vote
1
answer
852
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How spark reduce works here
How does spark reduce work for this example?
val num = sc.parallelize(List(1,2,3))
val result = num.reduce((x, y) => x + y)
res: Int = 6
val result = num.reduce((x, y) => x + (y * 10))
res: Int ...
- 387
1
vote
2
answers
426
views
Recursive reduce function in Python
I'm given a sequence tuple(range(1,5)) and I am supposed to write a recursive function with reduce to calculate the product 1*2*3*4*5 = 24.
I don't know how to do this recursively. I've tried looking ...
- 472
0
votes
2
answers
125
views
Nested loop on a list with a function
I got stuck on that:
a list y = (1,2,3...)
a function func(A,B)
a constant C
How can I express this situation with loops?
B1 = func(C , y[0])
B2 = func(B1 , y[1])
B3 = func(B2 , y[2]) #.... and so ...
0
votes
2
answers
129
views
Combine two pandas dataframes adding corresponding values pt2
So i have these CSV files I want to combine as follows:
file1.csv
Date,Time,Unique1,Common
blah,blah,55,92
file2.csv
Date,Time,Unique2,Common
blah,blah,12,25
I want a pandas dataframe where...
Date,...
