Python Cheat Sheet
Last Updated : 07/07/2022
Python is an open-source and versatile programming language used by thousands of web developers, data scientists, and software engineers. It is very popular because it has extensive support libraries, user-friendly data structures, and a vibrant support community.
This Python Cheat Sheet can serve as a quick reference for system administrators and network administrators.
We include all essential categories and items including: network programming libraries, keywords, variables and data types, strings, lists, and more.
Basic Python Libraries for Network Admin
Here is the list of basic Python libraries with a brief explanation.
Name | Explanation |
PIP | Package manager for Python. |
pypcap | Python interface to pcap a packet capture library. |
PyPI | Repository of open-source Python packages. |
Paramiko | It is a Python interface around SSH networking concepts. |
EDDIE Tool | Python agent used for system and network monitoring, security, and performance analysis. |
pycos | It provides an Asynchronous Socket class to convert Python's blocking socket to a non-blocking socket. |
Diesel | Framework to write reliable and scalable network applications in Python. |
NAPALM | A Python. |
Celery | It is a task queue implementation for Python web applications to asynchronously execute work outside the HTTP request-response cycle. |
Python Keywords
Python has a set of keywords (or reserved words) used to define the syntax of the coding. You can not use these words as identifiers, functions, or variable names. Here is a list of such keywords with examples.
Keyword | Explanation | Example |
False, True | Boolean value, result of comparison operations | False == (1 > 2), True == (1 < 2) |
and, or, not | Logical operators | x, y = True, False (x or y) == True # True (x and y) == False # True (not y) == True # True |
break | Ends loop prematurely | while(True): break print (“Hi How R U?”) |
continue | Finishes current loop | while(True): continue print (“200”) |
class
def |
Defines a new class
Defines a new function |
class Bear def __init__(self): self.content = 1.0 def drink(self): self.content = 0.0backs = Bear() backs.drink() |
if, elif, else | Used for a conditional program that starts with if, tries the elif, and finishes with else. | x = int(input(“type your value: “)) if x > 4: print(“Big”) elif x == 4: print(“Medium”) else: print(Small”) |
for, while | for a in [0,1,2,3]: print(a)b = 1 while b < 4: print(b) b = b + 1 |
|
in | Checks whether element is in sequence. | 30 in [10, 30, 40, 70] # True |
is | Checks whether both elements point to the same object. | a = b = 5 a is b # True [5] is [5] # False |
None | Empty value constant | def f(): a = 3 f() in None # True |
lamda | Function with no name | (lamda a: a + 4)(4) # returns 8 |
return | Terminates execution of the function and passes the flow of performance to the caller. | def incrementor(a): return a + 1 incrementor(3) # return 4 |
Data Types
In Python programming, everything is an object. Every value in Python is called an “object,” and every object has a specific data type.
There are various data types in Python. Some of the essential types are listed below:
- int An integer number that represents an object or number such as 3, 4, 5, etc.
- float Represents ‘floating-point numbers' such as 0.5, 1.25, 2.0, etc.
- Strings A collection of one or more characters put in a single quotes, double-quotes, or triple quotes.
Data Types | |
Text Type | str |
Numeric Types | int, float, complex |
Sequence Types | list, tuple, range |
Mapping Type | dict |
Set Types | set, frozenset |
Boolean Type | bool |
Binary Types | bytes, bytearray, memoryview |
Math Operators
Math operators in Python perform mathematical operations like addition, subtraction, multiplication, and division. Here we list all of the math operators with explanations and examples.
Keyword | Explanation | Example |
** | Exponent | 3 ** 2 = 9 |
% | Modulus/Remainder | 22 % 8 = 6 |
// | Integer division | 20 // 8 = 2 |
/ | Division | 22 / 8 = 2.75 |
* | Multiplication | 2 * 3 = 6 |
– | Subtraction | 8 – 2 = 6 |
+ | Addition | 2 + 8 = 10 |
== | Equal to | |
!= | Not equal to | |
< | Less than | |
> | Greater than | |
>= | Greater than or Equal to | |
<= | Less than or Equal to |
Network Services in Python
There are two levels of network services in Python.
- High-level access This service helps programmers access the application-level network protocols.
- Low-level access This service allows you to access the socket support for the operating systems by using Python libraries. You can use low-level access to implement connection-less and connection-oriented protocols for performing network programming.
There are several methods available that help network administrators manage the connections. Some of them are listed below.
Method | Explanation |
listen() | Used to establish and start TCP listeners. |
bind() | Used to bind-address to the socket. |
connect() | Used to make a connection with the TCP server. |
accept() | Used to accept TCP client connection, waiting until a connection arrives. |
recv() | Used to receive TCP messages. |
close() | Used to close a socket. |
Send() | Used to send messages. |
socket.gethostname() | Used to retrieve the hostname. |
mysocket.accept() | Returns a tuple with the remote address that has connected. |
mysocket.bind( address ) | Used to attach the specified address to the socket. |
mysocket.getpeername() | Used to get the remote address where the socket is connected. |
mysocket.connect( address ) | Used to assign the data sent through the socket to the given remote address. |
mysocket.getsockname() | Used to retrieve the address of the socket’s local endpoint. |
import socket socket.getservbyname(‘domain name') |
Used to obtain port number using the domain name. |
import socket socket.has_ipv6 |
Used to check support for IPV6. |
ipaddress.ip_address(‘192.168.0.1') | Used to assign an IP address. |
ipaddress.ip_network(‘192.168.0.1/24') | Used to determine the IPv4 or IPv6 version. |
host4=ipaddress.ip_interface(‘192.168.0.1/24') host4.network |
Used to obtain the network from an interface. |
net4=ipaddress.ip_network(‘192.168.0.1/24') net4.num_addresses |
Used to find the number of IP addresses in the specified network. |
net4=ipaddress.ip_network(‘192.168.0.1/24') net4.netmask |
Used to find the netmask of the specified IP address. |
Python Internet Modules
Here is the list of all Python internet modules.
Protocol | Explanation | Port | Python Module |
Gopher | Used to transfer documents. | 70 | Gopherlib, urllib |
Telnet | Used to open a command line on a remote computer. | 23 | telnetlib |
IMAP4 | Used for fetching emails from the mail server. | 143 | impalib |
POP3 | Used for fetching emails from the mail server. | 110 | poplib |
SMTP | Used for sending emails. | 25 | smtlib |
FTP | Used for file transfers. | 20 | Ftblib, urllib |
MNTP | Usenet news | 119 | mntplib |
HTTP | Used to access web pages over the internet. | 80 | Httplib, urllib |
Conclusion
We've included all useful Python commands, libraries, and code that you can use as a quick reference in the above guide. Feel free to let us know in the comments if you have any questions.