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question@mail.ru
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for _ in range . how does underscore work
📁 Advanced Python Topics, example
matrix = [[[0]*5] for _ in range(5)]there is such an expression, it creates five elements like 0 0 0 0 0. Can someone explain the mechanics of creation, the simpler the better.
For example
for x in range(5): print (x)range(5) - this is 0,1,2,3,4
and for each value starting from the first (0) the action print(x) is executed (prints the current value, in this case 0), after which it takes
answer@mail.ru
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If only natural numbers n are input, you can do this:
n = int(input())sum_of_factorials = 1curr_factorial = 1for i in range(2, n + 1): curr_factorial *= i sum_of_factorials += curr_factorialprint(sum_of_factorials)(You need 1!+2!+3!+...+n!, right? Or did you not make a typo? If not, then just multiply sum_of_factorials by 2 at the end and subtract 1).
This is quite simple dynamic programming. You don't need to recalculate each time from scratch.
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