What are generators in python

 

(13)GENERATORS:

Generators are functions that produce items one at a time and produce only when asked which can save a lot of memory.

for example:

import sys

def firstn(n):

    num, nums = 0, []

    while num < n:

        nums.append(num)

        num += 1

    return nums

sum_of_first_n = sum(firstn(1000000))

print(sum_of_first_n)

print(sys.getsizeof(firstn(1000000)), "bytes")

output = 499999500000

8697464 bytes

1.Creating generators:

A generator is defined like a normal function but with yeaild insted of return.

for example:

def my_generator():

    yield 1

    yield 2

    yield 3

2.Executing generators:

Calling a generator does not executes it, because it returns a generators object which is used to control execution.

To execute call the function next().