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| 1 | +#https://newdigitals.org/2024/01/23/basic-python-programming/#functions |
| 2 | +#Functions |
| 3 | +''' |
| 4 | +Python Function is a block of statements that return the specific task. |
| 5 | +The idea is to put some commonly or repeatedly done tasks together and make a function so that instead |
| 6 | +of writing the same code again and again for different inputs, we can do the function calls to reuse code contained in it over and over again. |
| 7 | +There are mainly two types of functions in Python. |
| 8 | +Built-in library function: These are Standard functions in Python that are available to use. |
| 9 | +User-defined function: We can create our own functions based on our requirements. |
| 10 | +We can define a function using the def keyword |
| 11 | +''' |
| 12 | +# A simple Python function |
| 13 | +def fun(): |
| 14 | + print("Welcome to Python") |
| 15 | + |
| 16 | + |
| 17 | +# Driver code to call a function |
| 18 | +fun() |
| 19 | +Output: |
| 20 | +Welcome to Python |
| 21 | +''' |
| 22 | +You can pass data, known as parameters, into a function. |
| 23 | +A function can return data as a result. |
| 24 | +Information can be passed into functions as arguments. |
| 25 | +Arguments are specified after the function name, inside the parentheses. |
| 26 | +You can add as many arguments as you want, just separate them with a comma: |
| 27 | +''' |
| 28 | +def add(num1: int, num2: int) -> int: |
| 29 | + """Add two numbers""" |
| 30 | + num3 = num1 + num2 |
| 31 | + |
| 32 | + return num3 |
| 33 | + |
| 34 | +# Driver code |
| 35 | +num1, num2 = 5, 15 |
| 36 | +ans = add(num1, num2) |
| 37 | +print(f"The addition of {num1} and {num2} results {ans}.") |
| 38 | +Output: |
| 39 | +The addition of 5 and 15 results 20. |
| 40 | +# some more functions |
| 41 | +def is_prime(n): |
| 42 | + if n in [2, 3]: |
| 43 | + return True |
| 44 | + if (n == 1) or (n % 2 == 0): |
| 45 | + return False |
| 46 | + r = 3 |
| 47 | + while r * r <= n: |
| 48 | + if n % r == 0: |
| 49 | + return False |
| 50 | + r += 2 |
| 51 | + return True |
| 52 | +print(is_prime(78), is_prime(79)) |
| 53 | + |
| 54 | +Output: |
| 55 | +False True |
| 56 | + |
| 57 | +#If you do not know how many arguments that will be passed into your function, add a * before the parameter name in the function definition. |
| 58 | +def my_function(*kids): |
| 59 | + print("The youngest child is " + kids[2]) |
| 60 | + |
| 61 | +my_function("Emil", "Tobias", "Linus") |
| 62 | +Output: |
| 63 | +The youngest child is Linus |
| 64 | + |
| 65 | +#Keyword Arguments: You can also send arguments with the key = value syntax |
| 66 | + |
| 67 | +def my_function(child3, child2, child1): |
| 68 | + print("The youngest child is " + child3) |
| 69 | + |
| 70 | +my_function(child1 = "Emil", child2 = "Tobias", child3 = "Linus") |
| 71 | +The youngest child is Linus |
| 72 | + |
| 73 | +#If you do not know how many keyword arguments that will be passed into your function, |
| 74 | +#add two asterisk: ** before the parameter name in the function definition. |
| 75 | +def my_function(**kid): |
| 76 | + print("His last name is " + kid["lname"]) |
| 77 | + |
| 78 | +my_function(fname = "Tobias", lname = "Refsnes") |
| 79 | +Output: |
| 80 | +His last name is Refsnes |
| 81 | +''' |
| 82 | +You can send any data types of argument to a function (string, number, list, dictionary etc.), |
| 83 | +and it will be treated as the same data type inside the function. |
| 84 | +E.g. if you send a List as an argument, it will still be a List when it reaches the function: |
| 85 | +''' |
| 86 | +def my_function(food): |
| 87 | + for x in food: |
| 88 | + print(x) |
| 89 | + |
| 90 | +fruits = ["apple", "banana", "cherry"] |
| 91 | + |
| 92 | +my_function(fruits) |
| 93 | + |
| 94 | +Output: |
| 95 | +apple |
| 96 | +banana |
| 97 | +cherry |
| 98 | + |
| 99 | +#To let a function return a value, use the return statement: |
| 100 | +def my_function(x): |
| 101 | + return 5 * x |
| 102 | + |
| 103 | +print(my_function(3)) |
| 104 | +print(my_function(5)) |
| 105 | +print(my_function(9)) |
| 106 | +Output: |
| 107 | +15 |
| 108 | +25 |
| 109 | +45 |
| 110 | + |
| 111 | +#A lambda function is a small anonymous function. A lambda function can take any number of arguments, but can only have one expression. |
| 112 | + |
| 113 | +#Add 10 to argument a, and return the result: |
| 114 | +x = lambda a : a + 10 |
| 115 | +print(x(5)) |
| 116 | +Output: |
| 117 | +15 |
| 118 | + |
| 119 | +#Lambda functions can take any number of arguments: |
| 120 | + |
| 121 | +#Multiply argument a with argument b and return the result: |
| 122 | +x = lambda a, b : a * b |
| 123 | +print(x(5, 6)) |
| 124 | +Output: |
| 125 | +30 |
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