Extract list element in Python

Question

This is my first python program. I use the below code to generate combinations for a given range.

for k in range(0, items+1):        
    for r in range(0, item         


        

Answer 1

• a) Use indexes:

  >>> [(1, 2, 3)][0][0]
  1
  

• b) I don't 100% understand this question, but instead of using a list comprehension as you have done, you can use list(itertools.combinations(...))

• c) I think you are misunderstanding what map() does. map(str, [1, 2, 3]) is equivalent to:

  [str(i) for i in [1, 2, 3]]
  

If you want to give [(0, 1)] a value, you can use a dictionary, but you have to use (0, 1) instead of [(0, 1)] because you would otherwise get TypeError: unhashable type: 'list'. If you want a "random value", I guess you can use the random module:

import random
{(0, 1) : random.randint(1,10)} # This is just an example, of course

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To store all the outputs in one list, you can use a massive list comprehension:

>>> [list(itertools.combinations(range(x, i), i-x)) for x in range(0, items+1) for i in range(0, items+1) if (i-x) > 0]
[[(0,)], [(0, 1)], [(0, 1, 2)], [(0, 1, 2, 3)], [(1,)], [(1, 2)], [(1, 2, 3)], [(2,)], [(2, 3)], [(3,)]]