def first_non_repeating(string):
    dict = {}
    for items in range(len(string)):
        key = string[items]
        if key not in dict:
            dict[key] = 1
        else:
            dict[key]+=1
    counter = 0
    for i in range(len(string)):
        if dict[string[i]] == 1:
            return string[i], counter
        counter += 1
    # for key, value in dict.items():
    #     if value == 1:
    #         return(key)
    #         break   

s = 'ABCDEFGHABCDE'
print(first_non_repeating(s))

from functools import wraps

def allow_only_int(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        if all([type(arg) == int for arg in args]):
            return func(*args, **kwargs)
        print("Invalid Argument. Should only be of type integer !!")
    return wrapper

@allow_only_int
def add_all(*args):
    total = 0
    for items in args:
        total+=items
    return total

print(add_all(1, 2, 3.2, 4.9, [1, 2, 3, 4]))

from functools import wraps
import time
def calculate_time(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        print(f"You are running {func.__name__} function")
        t1 = time.time()
        returned = func(*args, **kwargs) 
        t2 = time.time()
        total = t2 - t1
        print(f"This function took {total} seconds to run")
        return returned
    return wrapper

@calculate_time
def squares(l):
    return[items**2 for items in range(1, l+1)]

print(squares(10000))

from functools import wraps

def print_function_data(func):
    @wraps(func)
    def wrapper_function(*args, **kwargs):
        print(f"You are calling {func.__name__}")
        print(f"This function {func.__doc__}")
        return func(*args, **kwargs)
    return wrapper_function

@print_function_data
def add(a, b):
    '''takes two integers as input and returns their sum as output'''
    return a+b

print(add(5,6))

What is enumerate ?

Enumerate() method adds a counter to an iterable and returns it in a form of enumerate object. This enumerate object can then be used directly in for loops or be converted into a list of tuples using list() method.

list1 = []
n = 10
for items in range(n):
    a = int(input("Enter your items : "))
    list1.append(a)
print(list1)
for e, items in enumerate(list1):
    print(f"The index is {e} and the value of index is {items}")

What is a decorator ?

A decorator in Python is any callable Python object that is used to modify a function or a class. A reference to a function “func” or a class “C” is passed to a decorator and the decorator returns a modified function or class.

Sample Program of Decorator

def decorator_function(func):
    def msg():
        print("Hey...")
        func()
    return msg

@decorator_function
def deco1():
    print("This is a decorator function.")

deco1()

def deco2():
    print("This is also a decorator function")


# abc = decorator_function(deco2)
# abc()

*args – The special syntax *args in function definitions in python is used to pass a variable number of arguments to a function. It is used to pass a non-keyworded, variable-length argument list.

**kwargs – The special syntax **kwargs in function definitions in python is used to pass a keyworded, variable-length argument list. We use the name kwargs with the double star. The reason is because the double star allows us to pass through keyword arguments (and any number of them).

Sample Program using both *args and **kwargs

def f(*args, **kwargs):
    if kwargs.get('reverse_str') == True:
        return [i[::-1].title() for i in args]
    else:
        return [i.title() for i in args]

a = ['sayan', 'dey']
print(f(*a, reverse_str = True))