Python: Ultimate Cheat Sheet

🐍 Python Basics

Data Structures

Data types

Name	Type	Description	Example
Integer	int	Whole numbers	-3, 25, 300
Floating point	float	Number with a decimal point	-2.3, 4.6, 100.0
String	str	Ordered sequence of characters	"hello world!"
List	list	Ordered sequence of objects	[20, "hello", 4.6]
Dictionary	dict	Unordered Key:Value pairs	{"name":"Frankie", "surname":"Smith"}
Tuple	tup	Ordered immutable sequence of objects	[20, "hello", 4.6]
Set	set	Unordered collection of unique objects	{"a","b","c"}
Boolean	bool	Binary value	True or False

Strings

Method	Description	Example	Result
capitalize()	Convert first character to upper case
count()	Return number of times a specified value occurs in a string
encode()	Returns an encoded version of the string
format()	Format specified values in a string
index()	Return the index position of a specified value
join()	Convert the elements of an iterable into a string
lower()	Convert string into lower case
lstrip()	Trim the left portion of the string
replace()	Replace a specified value with a specified value
rindex()	Return the last position of a specified value
rsplit()	Split the string with a specified seperator and return a list
rsplit()	Trim the right portion of a string
splitlines()	Split the string at line breaks and return a list
strip()	Trim the string
title()	Convert the first character of each word to upper case
upper()	Convert string into upper case

Lists

Method	Description	Example	Result
append()
clear()
copy()
count()
extend()
index()
insert()
pop()
remove()
reverse()
sort()

Dictionaries

Method	Description	Example	Result
clear()
copy()
fromkeys()
get()
items()
keys()
pop()
popitem()
setdefault()
update()
values()

Tuples

Method	Description	Example	Result
count()	Return number of times a specified value occurs
index()	Return index position of a specified value

Sets

Method	Description	Example	Result
add()
clear()
copy()
difference()
difference_update()
discard()
intersection()
intersection_update()
isdisjoint()
issubset()
issuperset()
pop()
remove()
remove()
symmetric_difference()
symmetric_difference_update()
union()
update()

Date and time

Value	Description	Example
%a	Abbreviated weekday	Sun
%A	Weekday	Sunday
%b	Abbreviated month name	Jan
%B	Month name	January
%c	Date and time
%d	Day of month	01 to 31
%H	24 hour	00 to 23
%I	12 hour	01 to 12
%j	Day of year	001 to 366
%m	Month number	01 to 12
%M	Minute	00 to 59
%p	Time period	AM or PM
%S	Second	00 to 61
%U	Week number	00 to 53
%w	Weekday	0 to 6
%W	Week number	00 to 53
%x	Date
%X	Time
%y	Year without century	00 to 99
%Y	Year	2021
%Z	Time zone	GMT

Operators

Arithmetic operators

Name	Operator	Description	Example	Result
Addition	+	Add a and b	5+2	7
Subtraction	-	Subtract b from a	5-2	3
Multiplication	*	Multiply a by b	5*2	10
Division	/	Divide a by b	5/2	2.5
Modulus	%	Remainder of a divided by b	5%2	1
Exponent	**	Raise a to the power of b	5**2	25
Integer division	//	Divide a by b and only return integer	5//2	2

Comparison operators

Name	Operator	Description	Example	Result
Equal	==	True if a equals b	5==2	False
Not equal	!=	True if a is not equal to b	5!=2	True
Less than	<	True if a is less than b	5<2	False
Less than or equal	<=	True if a is less than or equal to b	5<=2	False
Greater than	>	True if a is greater than b	5>2	True
Greater than or equal	>=	True if a is greater than or equal to b	5>=2	True

Logical operators

Operator	Description	Example
and	Return True if both statements are true	x>2 and x<5
or	Return True if at least one statement is true	x==2 or x>5
not	Return False if the statement is true	not(x>2 and x<5)

Conditional Statements

Statement	Description
if	Execute code if condition is true
elif	Execute code if previous condition was false
else	Execute code if all of the previous conditions were false
pass	Skip executing code of condition is true

Conditional statement

if a > b:
    print("a is greater than b")
elif a == b:
    print("a and b are equal")
else:
    print("b is greater than a")

Nested if statement

if x > 5:
    print("Greater than five")
    if x > 10:
        print("and greater than ten")
    else:
        print("and less than ten")

Pass statement

if x > 5:
    pass

Loops

For loop

list = [1,2,3,4,5]

for element in list:
    print(element)

# Output: 1,2,3,4,5

Break statement

list = [1,2,3,4,5]

for element in list:
    if element == 3:
        print("Found!")
        break
    print(element)

# Output: 1,2,Found!

Continue statement

list = [1,2,3,4,5]

for element in list:
    if element == 3:
        print("Found!")
        continue
    print(element)

# Output: 1,2,Found!,4,5

Else statement

list = [1,2,3,4,5]

for element in list:
    print(element)
else:
    print("Finally finished!")

# Output: 1,2,3,4,5,Finally finished!

Range loop

for i in range(10):
    print(i)

# Output: 0,1,2,3,4,5,6,7,8,9

Range loop with indexing

for i in range(1,11):
    print(i)

# Output: 1,2,3,4,5,6,7,8,9,10

Nested loop

list = [1,2,3]

for element in list:
    for letter in "abc":
        print(element, letter)

# Output: 1a,1b,1c,2a,2b,2c,3a,3b,3c

While loop

x = 0

while x < 10:
    print(x)
    x += 1

# Output: 0,1,2,3,4,5,6,7,8,9,10

Infinite loop with break statement

x = 0

while True:
    if x == 5:
        break
    print(x)
    x += 1

# Output: 0,1,2,3,4

Functions

Function – a collection of instructions that can be initiated by calling a defined function.
Parameter – the input that you define for the function.
Argument – value for a given parameter.
Key word argument – used to make code more readable.
*args – used for unknown number of arguments. The function will receive a tuple of arguments.

Function

Create a function

def function1():
    print("Hi there.")
    print("Welcome aboard.")

function1()

# Output: Hi there. Welcome aboard.

Return function

def function2(x):
    return 5*x

print(function2(3))

# Output: 15

Multiple argument function

def function3(x, y):
    return x+y

print(function3(2,7))

# Output: 9

Function example

def function4(x):
    print(x)
    print("still in this function.")
    return 3*x

print(function4(4))

# Output: 4 still in this function. 12

Function variables

def greet(first_name, last_name):
    print(f"Hi {first_name} {last_name}.")
    print("Welcome aboard.")

greet("Frankie", "Smith")

# Output: Hi Frankie Smith. Welcome aboard.

BMI calculator example

Input values

name1 = "Frankie"
height1 = 2
weight1 = 90

name2 = "Kelvin"
height2 = 2.5
weight2 = 160

BMI function


def bmi_calculator(name, height, weight):
    bmi = weight / (height **2)
    print("bmi: ")
    print(bmi)
    if bmi < 25:
        return name + " is not overweight"
    else:
        return name + " is overweight"

Run function

result1 = bmi_calculator(name1, height1, weight1)
result2 = bmi_calculator(name2, height2, weight2)

# Output:
# bmi: 22.5
# bmi: 25.6

print(result1)
print(result2)

# Output:
# Frankie is not overweight
# Kelvin is overweight

Key-word argument

def function3(x, y):
    return x+y

print(function3(x=2, y=7))

# Output: 9

Arbitrary aruments: *args

*args



# Output:

Arbitrary key-word aruments: **kwargs

**kwargs



# Output:

Object Oriented Programming

🔢 Numpy

🐼 Pandas

⬛ PyCharm

Shortcuts

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Debugging

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Refactoring

1 thought on “🐍 Python: Ultimate Cheat Sheet”

Smt Sarasvati
December 31, 2021 at 2:41 pm

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