python stoped iterator while trying to create lists of sequences and inserting it in excel using panda

Question

I am trying to create a list of 6 numbers lists from 1 to 49 throw looping from 1 to 49 and creating all possible sets of 1 to 49 . the issue is that code stops at number 15 and in Pycharm nothing is being printed (excel file is being written but stops at 38759 record)

import itertools
import pandas as pd
stuff = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49]
all=[]

for L in range(0, len(stuff)+1):
    for subset in itertools.combinations(stuff, L):
        alist=list(subset)
        if len(subset)==6:
            all.append(alist)

all_tuple=tuple(all)

df = pd.DataFrame(all_tuple,columns=['z1','z2','z3','z4','z5','z6'])
print(df)
df.to_excel('test.xlsx')

Answer 1

If I understand correctly, you are trying to find the possible combinations of 6 numbers sampled from the list [1, 2, 3, ..., 49] without replacement.

But your code calculates the combinations of all lengths and then only saves those of length 6.

To get a clue as to why your code does not terminate quickly, consider the number of combinations of 6 numbers:

>>> print(len(list(itertools.combinations(range(1, 50), 6))))
13983816

So, if there are 14 million possible combinations of 6 numbers, imagine how many combinations there are of 7, 8, 9, ...

Here is some code to calculate only the 14 million combinations of length 6:

combs = list(itertools.combinations(range(1, 50), 6))

Or, if you really want to build the dataframe:

# Warning, this takes about 25 seconds
combs = itertools.combinations(range(1, 50), 6)
df = pd.DataFrame(combs, columns=['z1','z2','z3','z4','z5','z6'])

Bear in mind that this will take up quite a bit of memory. I'm not sure if Excel can handle 14 million rows so I didn't risk it.

Also, don't use reserved keywords for variable names. all is a built in Python function.