Generator basics (yield)

##################
def sq_nums(nums):
  for i in nums:
    yield (i+i)
###################

my_nums = sq_nums([1,2,3,4,5])

for num in my_nums:
  print(num)

2 4 6 8 10

# This is different from casting with list
my_nums = (x * x for x in [1,2,3,4,5])
print(my_nums)

<generator object <genexpr> at 0x7f9309bbd4d0>

# This would damage the performance in terms of speed and memory
my_nums2 = [x * x for x in [1,2,3,4,5]]
print(my_nums2)

[1, 4, 9, 16, 25]