learn_python3/Python3/OOPs_in_Python/generator.py at main · legionJP/learn_python3 · GitHub

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#---------------------------------------------------------------------------------------------------------------#
#                                        Generator
#---------------------------------------------------------------------------------------------------------------#

'''The generator will give you the iterator
Generators are lazy iterators created by generator functions (using yield)
or generator expressions (using (an_expression for x in an_iterator))
'''
#---------------------------------------------------------------------------------------------------------------#
# Function for  square Number


def square_number(num):
    result =[]
    for i in num:
        result.append(i*i)
    return result

my_num = square_number([11,22,33,44,55,66,77,88,99])
#my_num = [x*x for x in [1,2,3,4,5,6,7,8,9]] # list comprehension or generator expression

#---------------------------------------------------------------------------------------------------------------#
'''
Generator expressions are similar to list, dictionary and set comprehensions,
but are enclosed with parentheses.
The parentheses do not have to be present when
they are used as the sole argument for a function call
'''
my_num = (x*x for x in [1,2,3,4,5]) # generator expression
print(list(my_num)) #coverting into list item

print(my_num)

#---------------------------------------------------------------------------------------------------------------#
'''
Generator functions are similar to regular functions,
except that they have one or more yield statements in their
body. Such functions cannot return any values
(however empty returns are allowed if you want to stop the
generator early)'''

# Converting into generator Function (getting square by the help of generator )

def square_num(nums):
    for i in nums:
        yield i*i

my_nums = square_num([11,22,33,44,55,66])
print(my_nums) # printing the generater object address bcz  it does not hold the value in memory
#------------------------------------------------------------------------------------------------

# 1. Printing the value by iteration using the next or __next__ by iterator
# it yield the value one by one in every iteration


print(next(my_nums))
print(next(my_nums))
print(next(my_nums))
print(next(my_nums))
print(next(my_nums))
print(my_nums.__next__())
#print(next(my_nums))  # It will give the stopiteration error

#------------------------------------------------------------------------------------------------
# 2. using the loop

for square in my_nums:  # Run any 1 or 2, at a time
    print("Uing the loop ",square)


#------------------------------------------------------------------------------------------------
#                            Example of generator use
#------------------------------------------------------------------------------------------------

#1. Finding the top 10 squre
#------------------------------------------------------------------------------------------------

def topten():
    n=1
    while n<=10:
        sq = n*n
        yield sq
        n+=1
values = topten()
for i in values:
    print(i)

import mem_profile
import random
import time

#------------------------------------------------------------------------------------------------
# 2.

names = ['John', 'Carry', 'Adam', 'Gill' ,'Rohit', 'Ashwin']
majors = ['math','WK' , 'CompSci', 'Batting', 'Pullshot', 'Carromball']

print('Memory (Before): {}Mb'.format(mem_profile.memory_usage_resource()))


def people_list(num_people):
    result = []
    for i in range(num_people):
        person = {
                    'id': 1,
                    'name': random.choice(names),
                    'majors': random.choices(majors)

                  }
        result.append(person)
    return result

def people_generaotr(num_people):
    for i in range(num_people):
        person ={
                  'id': 1,
                  'name': random.choice(names),
                  'majors': random.choices(majors)

        }
        yield person

'''
t1 = time.process_time()
people = people_list(1000000)
t2 = time.process_time()

print('Memory (After): {}Mb'.format(mem_profile.memory_usage_resource()))
print('Took {} Seconds'.format(t2-t)
'''
t1 = time.process_time()
people = people_generaotr(1000000)
#people = list(people_generaotr(1000000))

t2 = time.process_time()

print('Memory (After): {}Mb'.format(mem_profile.memory_usage_resource()))
print('Took {} Seconds'.format(t2-t1))  # it didnt take any extra memory

#-------------------------------------------------------------------------