CODEWITHSUNDEEP
pythonpython-3.xdata-science
thanos
thanos

Reputation: 1

Creating sets using loops

Could anybody please help me understand the below statement in the code below it?

cartesian_powers = [ i+(a,) for i in cartesian_powers for a in A]

Specifically the role of i+(a,)?

Please explain the answer as much as possible.

Code:

A = {1, 2, 3}
k = 2

# Initialize every element as a tuple
cartesian_powers = [(a,) for a in A]

for j in range(k-1):
    cartesian_powers = [ i+(a,) for i in cartesian_powers for a in A]

print("Tuples  in {}^{}: {}".format(A,k,set(cartesian_powers)))
print("Size = {}".format(len(cartesian_powers)))

Upvotes: 0

Views: 44

Answers (1)

AbbeGijly
AbbeGijly

Reputation: 1211

Note that cartesian_powers is initialized using the same (a,) syntax, indicating the elements are tuples, each containing a single integer.

In [ i+(a,) for i in cartesian_powers for a in A], i and (a,) are each tuples, so the addition i+(a,) *concatenates the tuples, returning a two-integer tuple.

I think the addition syntax i+(a,) to represent tuple concatenation is causing the confusion.

Upvotes: 1

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