Inheritance allows us to define a class that inherits all the methods and properties from another class.
Parent class is the class being inherited from, also called base class.
Child class is the class that inherits from another class, also called derived class.
Python is an object oriented programming language.
Almost everything in Python is an object, with its properties and methods.
A Class is like an object constructor, or a “blueprint” for creating objects.
Note: This page shows you how to use LISTS as ARRAYS, however, to work with arrays in Python you will have to import a library, like the NumPy library.
Arrays are used to store multiple values in one single variable: Continue reading Python Arrays
A lambda function is a small anonymous function.
A lambda function can take any number of arguments, but can only have one expression.
lambda arguments : expression
The expression is executed and the result is returned:
Add 10 to argument a, and return the result:
x = lambda a : a + 10
print(x(5))
Lambda functions can take any number of arguments: Continue reading Python Lambda
A function is a block of code which only runs when it is called.
You can pass data, known as parameters, into a function.
A function can return data as a result.
In Python a function is defined using the def keyword:
def my_function():
print("Hello from a function")
To call a function, use the function name followed by parenthesis: Continue reading Python Functions
A for loop is used for iterating over a sequence (that is either a list, a tuple, a dictionary, a set, or a string).
This is less like the for keyword in other programming languages, and works more like an iterator method as found in other object-orientated programming languages.
With the for loop we can execute a set of statements, once for each item in a list, tuple, set etc. Continue reading Python For Loops
Python has two primitive loop commands:
With the while loop we can execute a set of statements as long as a condition is true.
Print i as long as i is less than 6:
i = 1 while i < 6: print(i) i += 1
Note: remember to increment i, or else the loop will continue forever.
Python supports the usual logical conditions from mathematics:
These conditions can be used in several ways, most commonly in “if statements” and loops.
An “if statement” is written by using the if keyword. Continue reading Python If … Else
Python has a set of built-in methods that you can use on dictionaries.
| Method | Description |
|---|---|
| clear() | Removes all the elements from the dictionary |
| copy() | Returns a copy of the dictionary |
| fromkeys() | Returns a dictionary with the specified keys and value |
| get() | Returns the value of the specified key |
| items() | Returns a list containing a tuple for each key value pair |
| keys() | Returns a list containing the dictionary’s keys |
| pop() | Removes the element with the specified key |
| popitem() | Removes the last inserted key-value pair |
| setdefault() | Returns the value of the specified key. If the key does not exist: insert the key, with the specified value |
| update() | Updates the dictionary with the specified key-value pairs |
| values() | Returns a list of all the values in the dictionary |
A dictionary can contain dictionaries, this is called nested dictionaries.
Create a dictionary that contain three dictionaries:
myfamily = {
"child1" : {
"name" : "Emil",
"year" : 2004
},
"child2" : {
"name" : "Tobias",
"year" : 2007
},
"child3" : {
"name" : "Linus",
"year" : 2011
}
}
Or, if you want to add three dictionaries into a new dictionary: Continue reading Python – Nested Dictionaries