Python Basics & Strings Cheat Sheet

A Programming › Python cheat sheet in English by Nouha_Thabet

Python Data Science

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Hello World in Python

print("Hello World!")

Python Comments

Example 1 `#This is a comment`
Example 2 `#This is a comment #written in #more than just one line`
Example 3 `""" This is a comment written in more than just one line """`

Python Variables

  x = "How old are you ?" #x is of type str  
print(x) 
 >>> How old are you ?


 x = 25 #x now is of type int 
 print(x) 
 >>> 25

Python 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`
Get the data type of a variable "var"
`type(var)`

Python Data Types Examples

Example	Data Type
`x = "Color"`	`list`
`x = 1`	`int`
`x = 1.2`	`float`
`x = 2j`	`complex`
`x = ["Blue","Red","Yellow"]`	`list`
`x = ("Blue","Red","Yellow")`	`tuple`
`x = range(8)`	`range`
`x={"Age":25,"Height":1.72}`	`dict`
`x = {"Pink","Red"}`	`set`
`x = frozenset({"Pink","Red"})`	`frozenset`
`x = True`	`bool`
`x = b"Color"`	`bytes`
`x = bytearray(8)`	`bytearray`
`x = memoryview(bytes(8))`	`memoryview`
Get the data type of x :
`x = "Color" print(type(x)) >>> str`

Python Casting

Casting is used to specify a type on to a variable and this is done using constructor functions.
Examples
x = int(5) #x = 5
x = int(2.8) #x = 2
x = float(5) #x = 5.0
x = float(2.8) #x = 2.8

Python Strings

Operations on strings and examples:
Multiline strings
`x = """ This is a` `multiline string"""`
Get the character at a specific position
`x = "Python Programming" print(x[1]) #print character at position 1 >>> y`
Slicing
`x = "Python Programming" print(x[3:5]) >>> ho`
Negative Indexing
`x = "Python Programming" print(x[-15:-13]) >>> ho`
String Length
`x = "Hello" print(len(x)) >>> 5`
Remove any whitespace from the beginning or the end
`x = " Hello " print(x.strip()) #return "Hello"`
Return the string in lower case
`x = Hello print(x.lower()) #return "hello"`

Python Strings

Return the string in upper case
`x = Hello print(x.upper()) #return "HELLO"`
Replace a string with another string
`x = "Hello" print(x.replace("He","A")) #return "Allo"`
Choose a separator and split string into substrings
`x = "Python Programming" print(x.split(" ")) # return ['Python' , 'Programming']`
Check if a string is present in a text
`txt = "Tunisia is a North African country" x = "North" in txt print(x) # return True`
Concatenation
`x = "Hello" y = "World" z = x + " " + y print(z) # return "Hello World"`
Insert numbers into strings
`quantity = 3 itemno = 567 price = 49.95 myorder = "I want {} pieces of item {} for {} dollars." print(myorder.format(quantity, itemno, price))`

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