"# python-learnings"

Errors : ValueError NameError FileNotFoundError

Static Code Analysis: pylint myexample.py -r y

1. Tuple Unpacking my_tuples = ( ("Naga", 35, "John Wick") , ("Ash", 30, "DDLJ") , ("Ayya", 60, "MI")) for a, b, c in my_tuples: print(a) print(b) print(c)

print('*'*108)

#my_list = [[1,2,3,4,5] , [10,20,30,40,50], [100,200,300,400,500, 600]] #ValueError: too many values to unpack (expected 5) my_list = [[1,2,3,4,5] , [10,20,30,40,50], [100,200,300,400,500]] for a,b,c,d,e in my_list: print( a ) print( b ) print( c ) print( d ) print( e )

2. While statement can have else block while x<5 : print(f'current val of x is {x}') x = x+1 else: print(f'exited while loop ; x val is {x} ; not less than 5')

3. try except finally statement can have else block def ask_for_input(): while True: try: num = int(input("Please input a number : ")) except: print("Oh... Not a number") continue else: print("We got a number") break finally: print("End of try/except/finally") print("I always run")

4. Generators ex: range function for num in range(5): print(num)

print('*'*108)

for num in range(0,10,3): print(num)

5. Enumerators ex : enumerate function my_name = "Nagaraja" for index, value in enumerate(my_name): print(index) print(value) print("\n")

print("*"*108)

my_list = ["Nagaraja", "Naveen", "Smita", "Mangala"] for index, value in enumerate(my_list): print(index) print(value)

6. zip function my_list1 = [1,2,3,4] my_list2 = ["Mangala", "Naveen", "Smita", "Nagaraja"] my_list3 = [10,20,30,40]

for item in zip(my_list1, my_list2, my_list3): print(item) print("\n")

for a,b,c in zip(my_list1, my_list2, my_list3): print(a) print(b) print(c) print("\n")

7. List Comprehension celcius = [0,10, 20,30,40,50] #for loop farenheit = [ ((9/5)*temp + 32) for temp in celcius] print(farenheit)

#for with if even_nums = [ num for num in range(0,11) if num %2==0] print(even_nums)

#for with if else nums = [ num if num%2==0 else (num**2) for num in range(0,11) ] print(nums) #even num ; squared odd nums

#nested for loops my_list2 = [ x*y for x in [1,2,3] for y in [1,10,100]]

8. help(mylist.insert) # gives documentation

9. Functions - Positional def add_numbers_positional(num1, num2, num3:int): return num1+num2

result = add_numbers_positional(1,2,3) print(result)

10. Functions - Keyword (Notice * in the method arguments) def add_numbers_keyword(*, num1, num2, num3:int): return num1+num2+num3 result = add_numbers_keyword(num1=1, num2=2, num3=3) print(result)

11. Tuple unpacking with python function def employee_month(employee_hours): emp_max_hours = 0 emp_max_name = "" emp_max_age = 0

    for emp_name, emp_hours, emp_age in employee_hours: if emp_hours > emp_max_hours: emp_max_hours = emp_hours emp_max_name = emp_name emp_max_age = emp_age else: pass

    return (emp_max_name, emp_max_hours, emp_max_age)

best_employee = employee_month(employee_hours) print(best_employee)

12. *args - tuple pass arbitrary number of arguments. it will be stored as tuple def myfunc(*args): print(args) return sum(args) * 0.05

print(myfunc(10 ,20 ,30 ,40 ,50))

13. **kwargs - keyword arguments - stored as dictionary def myfunc(**kwargs): print(kwargs) if 'fruit' in kwargs: print(f'fruit {kwargs['fruit']} is present') else: print(f'fruit not present')

myfunc( veggie = 'Leaf', milk = 'Cow')

14. args and kwargs def my_food(*args, **kwargs): print(args) print(kwargs) print(f"I eat {args[1]} {kwargs['food']}")

my_food(3, 2, 4, 5, 6, 8, rice="White", food="eggs", fruit='Banana')

15. map function for item in map(square, mylist): print(item)

my_list_2 = list(map(square, mylist)) print(my_list_2)

16. filter function def is_even(num): return num%2==0

my_nums = [1,2,3,4,5,6,7]

even_nums = list(filter(is_even , my_nums)) print(even_nums)

17. Lambda or Ananymous function my_list = [1,2,3,4,5, 6, 7, 8] sq_list = list(map(lambda num: num**2, my_list)) print(sq_list)

even_list = list(filter(lambda num : num%2==0, my_list)) print(even_list)

18. SCOPE - LEGB Rule L - Local E - Enclosing function locals G - Global (Module) B - Built In (Python)

19. Special Dunder methods class Book(): def init(self, title, author, pages): self.title = title self.author = author self.pages = pages

    def str(self): return str({'title':self.title, 'author':self.author})

    def len(self): return self.page

20. Pypi - repository of third party python packages pip install requests

21. name == "main" if name == "main": print("one.py is run directly") func() say_hello() say_hi() else: print("one.py is imported")

from import from <package.module> import

23. asyncio - refer concurrencyasyncio #await coroutine - runs the coroutine #create task - creates task #await task - waites till the task is run

    #b, c = await asyncio.gather(brew_coffee(), toast_bagel()) - run multiple coroutines together #res = await brew_coffee() - run 1 coroutine