Python basics

Table of contents

• Comments
• Importing Modules
• Strings
• Advanced strings
• Math
• Variables & Methods
• Functions
• Boolean Expressions
• Relational operators
• Conditional Statements
• Lists
• Touples
• Dictionaries
• Looping
• Sockets

Comments

# this is a comment

Importing Modules

From what import what as alias 

#sys, os, datetime often used 
# Alias if defined instead of writing datetime, you can wtite dt if specified 

Strings

print("string") 
print('string') 
print("""String 
multiple lines""") 
print("string 1 " + "is awesome") 

Advanced strings

[0] #first letter 
[-] #last letter 
.split() #splits words into list 
.join 
# escaping \
.strip() # strip spaces
print("Sentence {}".format(variable)) #concatenating

Math

1. */+- all supported
2. ** exponents
3. % modulo
4. // -dividing without leftovers

Variables & Methods

variable_name = value 
#Method call with dot . Ex. 
value.upper()
 
.upper()
.lower()
.title()
.len(variable) #broj karaktera
.int() #returns integer, does not round!
.float() # returns float
.type()

Functions

#defining functions
def function_name(params): 
    variables with indentation 

# Calling function 
function_name(params) 

Boolean Expressions

True, False

Relational operators

AND OR

Conditional Statements

if:
 else: 

if:
 elif:
 else: 

Lists

1. []
2. Live in brackets
3. Can be changed

list_name = [list_items, "separated by comma"] 
# [index] - starts from 0 
# [start_index:end_index] 
# [start:] - everything after starting index 
# [:stop] - everything until stop index 
# [-1] - very last item 
.len() 
.append(what) #at end 
.pop(index) #delete last or (index) 

Tuples

1. ()
2. Unchangeable
3. Can just be printed or read

tuple_name = (list_items, 'separated by comma') 

Dictionaries

1. {}
2. Key, value

var_name = {key:value, key:value, key: [values, values]} 
employees[key] = [value]  # adding
.update({"key": [values]}) # adding 
.get(key)  # returns value 

Looping

for x in list:
   print(x)

while condition: 
  # what_happens 
  iteraror ++ 

Sockets

1. To connect 2 ports together
2. Connecting ports and ip addreses
3. Connect to open port etc.

s= socket.socket(socket.AD_INET, socket.SOCK_STREAM)