From 50228fa7b71df4cfad162da5721089d54c20cbb4 Mon Sep 17 00:00:00 2001 From: Asabeneh Date: Thu, 8 Jul 2021 03:28:42 +0300 Subject: [PATCH] functions --- 11_Day_Functions/11_functions.md | 84 +++++++++++++++++--------------- 1 file changed, 46 insertions(+), 38 deletions(-) diff --git a/11_Day_Functions/11_functions.md b/11_Day_Functions/11_functions.md index a4695d5..f7bd8f9 100644 --- a/11_Day_Functions/11_functions.md +++ b/11_Day_Functions/11_functions.md @@ -9,10 +9,9 @@ Author: Asabeneh Yetayeh
- First Edition: Nov 22 - Dec 22, 2019 + Second Edition: July, 2021 - [<< Day 10](../10_Day_Loops/10_loops.md) | [Day 12 >>](../12_Day_Modules/12_modules.md) @@ -33,20 +32,23 @@ - [Default and Arbitrary Number of Parameters in Functions](#default-and-arbitrary-number-of-parameters-in-functions) - [Function as a Parameter of Another Function](#function-as-a-parameter-of-another-function) - [💻 Exercises: Day 11](#-exercises-day-11) + - [Exercises: Level 1](#exercises-level-1) + - [Exercises: Level 2](#exercises-level-2) + - [Exercises: Level 3](#exercises-level-3) # 📘 Day 11 ## Functions -So far we have seen many built-in python functions. In this section, we will focus on custom functions. What is a function? Before we start making functions, lets learn what a function is and why we need them? +So far we have seen many built-in Python functions. In this section, we will focus on custom functions. What is a function? Before we start making functions, let us learn what a function is and why we need them? ### Defining a Function -A function is a reusable block of code or programming statements designed to perform a certain task. To define a function, Python provides the _def_ keyword. The following is the syntax for defining a function. The function block of code is executed only if we call it. +A function is a reusable block of code or programming statements designed to perform a certain task. To define or declare a function, Python provides the _def_ keyword. The following is the syntax for defining a function. The function block of code is executed only if the function is called or invoked. ### Declaring and Calling a Function -When we make a function we call it declaring a function. When we start using the it we call it calling or invoking a function. Function can be declared with or without parameters. +When we make a function, we call it declaring a function. When we start using the it, we call it *calling* or *invoking* a function. Function can be declared with or without parameters. ```py # syntax @@ -83,7 +85,7 @@ add_two_numbers() ### Function Returning a Value - Part 1 -Function can also return values, if a function does not return any, the value of the function is None. Lets rewrite the above functions using return. From now on, we get a value when calling the function, instead of printing it. +Function can also return values, if a function does not have a return statement, the value of the function is None. Let us rewrite the above functions using return. From now on, we get a value from a function when we call the function and print it. ```py def generate_full_name (): @@ -115,7 +117,7 @@ In a function we can pass different data types(number, string, boolean, list, tu codes codes # Calling function - function_name(parameter) + print(function_name(argument)) ``` **Example:** @@ -147,11 +149,11 @@ def sum_of_numbers(n): for i in range(n+1): total+=i print(total) -sum_of_numbers(10) # 55 -sum_of_numbers(100) # 5050 +print(sum_of_numbers(10)) # 55 +print(sum_of_numbers(100)) # 5050 ``` -- Two Parameter: A function may or may not have a parameter or parameters. A function may have two or more parameters. If our function takes parameters we should call it with arguments. Let's check a function with two parameters: +- Two Parameter: A function may or may not have a parameter or parameters. A function may also have two or more parameters. If our function takes parameters we should call it with arguments. Let us check a function with two parameters: ```py # syntax @@ -160,7 +162,7 @@ sum_of_numbers(100) # 5050 codes codes # Calling function - function_name(arg1, arg2) + print(function_name(arg1, arg2)) ``` **Example:** @@ -181,7 +183,7 @@ def calculate_age (current_year, birth_year): age = current_year - birth_year return age; -print('Age: ', calculate_age(2019, 1819)) +print('Age: ', calculate_age(2021, 1819)) def weight_of_object (mass, gravity): weight = str(mass * gravity)+ ' N' # the value has to be changed to a string first @@ -200,7 +202,7 @@ def function_name(para1, para2): codes codes # Calling function -function_name(para1='John', para2='Doe') # the order of arguments does not matter here +print(function_name(para1 = 'John', para2 = 'Doe')) # the order of arguments does not matter here ``` **Example:** @@ -210,12 +212,12 @@ def print_fullname(firstname, lastname): space = ' ' full_name = firstname + space + lastname print(full_name) -print_fullname(firstname='Asabeneh', lastname='Yetayeh') +print(print_fullname(firstname = 'Asabeneh', lastname = 'Yetayeh')) def add_two_numbers (num1, num2): total = num1 + num2 print(total) -add_two_numbers(num2=3, num1=2) # Order does not matter +print(add_two_numbers(num2 = 3, num1 = 2)) # Order does not matter ``` ### Function Returning a Value - Part 2 @@ -272,7 +274,7 @@ print(is_even(7)) # False ```py def find_even_numbers(n): evens = [] - for i in range(n+1): + for i in range(n + 1): if i % 2 == 0: evens.append(i) return evens @@ -311,10 +313,10 @@ def generate_full_name (first_name = 'Asabeneh', last_name = 'Yetayeh'): print(generate_full_name()) print(generate_full_name('David','Smith')) -def calculate_age (birth_year,current_year = 2019): +def calculate_age (birth_year,current_year = 2021): age = current_year - birth_year return age; -print('Age: ', calculate_age(1819)) +print('Age: ', calculate_age(1821)) def weight_of_object (mass, gravity = 9.81): weight = str(mass * gravity)+ ' N' # the value has to be changed to string first @@ -345,7 +347,7 @@ def sum_all_nums(*nums): for num in nums: total += num # same as total = total + num return total -print(sum_all_nums(2, 3, 5)) +print(sum_all_nums(2, 3, 5)) # 10 ``` ### Default and Arbitrary Number of Parameters in Functions @@ -355,7 +357,7 @@ def generate_groups (team,*args): print(team) for i in args: print(i) -generate_groups('Team-1','Asabeneh','Brook','David','Eyob') +print(generate_groups('Team-1','Asabeneh','Brook','David','Eyob')) ``` ### Function as a Parameter of Another Function @@ -366,17 +368,19 @@ def square_number (n): return n * n def do_something(f, x): return f(x) -print(do_something(square_number, 3)) +print(do_something(square_number, 3)) # 27 ``` -🌕 You achieved quite a lot so far. Keep going! You have just completed day 11 challenges and you are 11 steps a head in to your way to greatness. Now do some exercises for your brain and for your muscle. +🌕 You achieved quite a lot so far. Keep going! You have just completed day 11 challenges and you are 11 steps a head in to your way to greatness. Now do some exercises for your brain and muscles. ## 💻 Exercises: Day 11 +### Exercises: Level 1 + 1. Declare a function _add_two_numbers_. It takes two parameters and it returns a sum. 2. Area of a circle is calculated as follows: area = π x r x r. Write a function that calculates _area_of_circle_. 3. Write a function called add_all_nums which takes arbitrary number of arguments and sums all the arguments. Check if all the list items are number types. If not do give a reasonable feedback. -4. Temperature in °C can be converted to °F using this formula: °F = (°C x 9/5) + 32. Write a function which converts °C to °F, _convert_celcius_to-fahrenheit_. +4. Temperature in °C can be converted to °F using this formula: °F = (°C x 9/5) + 32. Write a function which converts °C to °F, _convert_celsius_to-fahrenheit_. 5. Write a function called check-season, it takes a month parameter and returns the season: Autumn, Winter, Spring or Summer. 6. Write a function called calculate_slope which return the slope of a linear equation 7. Quadratic equation is calculated as follows: ax² + bx + c = 0. Write a function which calculates solution set of a quadratic equation, _solve_quadratic_eqn_. @@ -395,7 +399,7 @@ print(reverse_list1(["A", "B", "C"])) ```py food_staff = ['Potato', 'Tomato', 'Mango', 'Milk']; -print( add_item(food_staff, 'Meat')) # ['Potato', 'Tomato', 'Mango', 'Milk','Meat']; +print(add_item(food_staff, 'Meat')) # ['Potato', 'Tomato', 'Mango', 'Milk','Meat']; numbers = [2, 3, 7, 9]; print(add_item(numbers, 5)) [2, 3, 7, 9, 5] ``` @@ -409,19 +413,20 @@ numbers = [2, 3, 7, 9]; print(remove_item(numbers, 3)) # [2, 7, 9] ``` -13. Declare a function named sum_of_numbers. It takes a number parameter and it adds all the numbers in that range. +13. Declare a function named sum_of_numbers. It takes a number parameter and it adds all the numbers in that range. ```py print(sum_of_numbers(5)) # 15 print(sum_all_numbers(10)) # 55 print(sum_all_numbers(100)) # 5050 - - ``` -14. Declare a function named sum_of_odds. It takes a number parameter and it adds all the odd numbers in that range. -15. Declare a function named sum_of_even. It takes a number parameter and it adds all the even numbers in that - range. -16. Declare a function named evens_and_odds . It takes a positive integer as parameter and it counts number of evens and odds in the number. +14. Declare a function named sum_of_odds. It takes a number parameter and it adds all the odd numbers in that range. +15. Declare a function named sum_of_even. It takes a number parameter and it adds all the even numbers in that - range. + +### Exercises: Level 2 + +1. Declare a function named evens_and_odds . It takes a positive integer as parameter and it counts number of evens and odds in the number. ```py print(evens_and_odds(100)) @@ -429,14 +434,17 @@ print(sum_all_numbers(100)) # 5050 # The number of evens are 51. ``` -17. Call your function factorial, it takes a whole number as a parameter and it return a factorial of the number -18. Call your function _is_empty_, it takes a parameter and it checks if it is empty or not -19. Write different functions which take lists. They should calculate_mean, calculate_median, calculate_mode, calculate_range, calculate_variance, calculate_std (standard deviation). -20. Write a function called is_prime, which checks if a number is prime. -21. Write a functions which checks if all items are unique in the list. -22. Write a function which checks if all the items of the list are of the same data type. -23. Write a function which check if provided variable is a valid python variable -24. Go to the data folder and access the countries-data.py file. +1. Call your function factorial, it takes a whole number as a parameter and it return a factorial of the number +1. Call your function _is_empty_, it takes a parameter and it checks if it is empty or not +1. Write different functions which take lists. They should calculate_mean, calculate_median, calculate_mode, calculate_range, calculate_variance, calculate_std (standard deviation). + +### Exercises: Level 3 + +1. Write a function called is_prime, which checks if a number is prime. +1. Write a functions which checks if all items are unique in the list. +1. Write a function which checks if all the items of the list are of the same data type. +1. Write a function which check if provided variable is a valid python variable +1. Go to the data folder and access the countries-data.py file. - Create a function called the most_spoken_languages in the world. It should return 10 or 20 most spoken languages in the world in descending order - Create a function called the most_populated_countries. It should return 10 or 20 most populated countries in descending order.