Language feature: generators and yield keyword

[tusharsadhwani]

Generator functions are functions that contain the yield keyword.

Generator functions, instead of returning a value, return a generator object, which when called with the top level next() function, resumes the function and keeps running it until it yields a value, and then pauses its execution.

For example:

def generator():
    print("This runs first")
    yield 1
    print("This runs in between")
    yield 2
    print("This runs last")

gen = generator()
print(next(gen))
print(next(gen))
print(next(gen, 3))

Produces this output:

This runs first
1
This runs in between
2
This runs last
3