Introduction to Python
Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation.
Python is dynamically typed and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented and functional programming. It is often described as a "batteries included" language due to its comprehensive standard library.
Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language and first released it in 1991 as Python 0.9.0. Python 2.0 was released in 2000. Python 3.0, released in 2008, was a major revision not completely backward-compatible with earlier versions. Python 2.7.18, released in 2020, was the last release of Python 2.
Python consistently ranks as one of the most popular programming languages.
Keywords
Python Keywords
| and |
del |
from |
None |
True |
| as |
elif |
global |
nonlocal |
try |
| assert |
else |
if |
not |
while |
| break |
except |
import |
or |
with |
| class |
False |
in |
pass |
yield |
| continue |
finally |
is |
raise |
|
| def |
for |
lambda |
|
|
Arithmetic Operators
Just like mathematics, Python has several arithmetic operators that you can use for computation. They are:
Python Arithmetic Operators
| Operator |
Meaning |
Example |
Outcome |
| + |
Add |
x, y = 3, 4
z = x + y |
z is equal to 7 |
| - |
Subtract |
x, y = 3, 4
z = x - y; |
z is equal to -1 |
| * |
Multiply |
x, y = 3, 4
z = x * y |
z is equal to 12 |
| / |
Divide |
x, y = 6, 2
z = x / y |
z is equal to 3 |
| % |
Modulus |
x, y = 5, 3
z = x % y |
z is equal to 2 |
| ** |
Exponent |
x, y = 2, 3
z = x ** y |
z is equal to 8 |
| // |
Floor Division |
x, y = 20, 12
z = x // y |
z is equal to 1 |
There are a couple of these operators that need some explanation. First the modulus operator will return the remainder for a division
- 10 % 3 results in 1 be case 10 / 3 = 3 with a remainder of 1
- 12 % 7 results in 5 Because 12 / 7 = 1 with a remainder of 5
The floor division operator gives a division of a number where the numbers after the decimal point are truncated.
- 15 // 4 is 3 because 4 goes into 15 three times; the remainder is truncated.
In other high level languages whole number division gives you a whole number result. This is not the case in Python. If you divide two whole numbers like
Escape Characters
The following table is a complete list of escape characters that can be used to format strings.
Python Escape Characters
| Character |
Description |
| \a |
Bell |
| \b |
Backspace |
| \Cx |
Control-x |
| \e |
Escape |
| \f |
Formfeed |
| \M-\C-x |
Meta-Control-x |
| \n |
Newline |
| \r |
Carriage Return |
| \s |
Space |
| \t |
Tab |
| \v |
Vertical Tab |
| \x |
Character x |
| \xnn |
Hexadecimal notation. Where n is in the range of 0-9, a-f or A-F |
Bitwise Operators
Bitwise operators in Python
| Operator |
Meaning |
Example |
| & |
Bitwise AND |
x& y = 0 (0000 0000) |
| | |
Bitwise OR |
x | y = 14 (0000 1110) |
| ~ |
Bitwise NOT |
~x = -11 (1111 0101) |
| ^ |
Bitwise XOR |
x ^ y = 14 (0000 1110) |
| >> |
Bitwise right shift |
x>> 2 = 2 (0000 0010) |
| << |
Bitwise left shift |
x<< 2 = 40 (0010 1000) |
Links of Interest