Basics

In Python the indentation of code is important. Everything that is indented on the same level belongs to a block.

Variables

Variables store values.

name = "me"
age = 39

Variables can't start with a number and can't have character like % or !.

We also can't use python keywords like if,for,while...

Expressions and Statements

Expression is any code that returns a value. 1+1

A statement is an operation on a value - we are doing something with the value. print(1+1)

Comments

Everything after # is ignored and can be used as comment # This is a comment

Data types

string - name = "hans"

integer - age = 2

float - temp = 2.9

boolean - isEven = True

We can check what data type a variable has with type().

Python automatically detects type of variables.

To check if something is of type string

name = "hans"
type(name) == str

#or

isinstance(name,str)

To convert int into float we can use the class-constructor of the datatype class temp = float(2)

age = int("20") -> becomes an int

The conversion is called casting

If these conversions fail we actually get an error in the console.

Operators

assignment operator = - assigns a value to a variable

Arithmetic operators

+ #addition
- #subtraction
* #multiplication
/ #division
% #remainder
** #squared
// #floor division - does the division and rounds down to the nearet whole number

We can combine arithmetic with assignment operator

+=, *= ... age += 8 -> age = age +8

Comparison operation

a == b #- Equal
a != b  #- Not equal
a > b  #- Greater
a < b #- Smaller

Boolean operators

not - #True when false
and - # both conditions have to be true
or - # one of the conditions have to be true

or returns the first not false value otherwise it returns the last operand

print(False or 'hey') # -> 'hey'
print(True or 'hey') # -> True
print(1 or 0) # -> 1

and only evaluates the second argument if the first is true. If the first argument is falsy it returns that argument - otherwise it evaluates the seconds argument.

print(0 and 1) # -> 0
print(False and 'hey') # -> False
print('hey' and 'hi') # -> hi

Bitwise operators

```py & # performs binary AND | # performs binary OR ^ # performs binary XOR ~ # performs binary NOT << # shift left operation

shift right operation