Python syntax cheat sheet

Python cheat sheet

txt = "this is a wild string"

print(txt.replace("i", "x"))  # print string with all i characters replaced with x
print(txt.replace("i", "x", 2))  # print string with first two i characters found with x
print(txt.upper())  # print string in all uppercase letters
print(txt.lower())  # print string in all uppercase letters

print(ord('A'))  # print the ordinal value of a character
print(chr(95))  # print character from its ordinal value
print('Yes' * 5) # print string Yes 5 times

# Reference strings by index
print(txt[0])  # print first letter of string from starting index
print(txt[0:2])  # print first two letters from starting index
print(txt[1:])  # print all characters except the first letter
print(txt[0::2])  # print every second character
print(txt[::-1])  # print string in reverse
print(txt[-1])  # print the last character in a string
print(txt[-2:])  # print the last who characters in a string

# check if a wild is found in txt
if "wild" in txt:
  print("wild is found in txt")

# check if a blah is not found in txt
if "blah" not in txt:
  print("is not found in txt")

# Check if txt starts with this
if txt.startswith("this"):
  print("Starts with this")

# check if txt ends with ing
if txt.endswith("ing"):
  print("Ends with ing")

# Split a string into a tuple when the delimiter is first encountered
txt = 'random-data'

data_split = txt.partition('-')
print(data_split)
# output ('random', '-', 'data')

len(txt)  # Return length of string

# loop through each character in string
for char in txt:
  print(char)

# Display price with commas and 2 digit precision
price = 9749000
display_price = f"My price {price:,.2f}"
print(display_price)


fruits = ['orange', 'apple', 'pear', 'banana', 'kiwi', 'apple', 'banana']
fruits.count('apple')  # count number of apples found in list
# output 2
fruits.count('tangerine')  # count number of tangerines in list
# output 0
fruits.index('banana')  # find the first index of banana
# output 3
fruits.index('banana', 4)  # Find next banana starting a position 4
# output 6
fruits.reverse()  # reverse fruits array
fruits
# output ['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange']
fruits.append('grape')  # append grape at the end of array
fruits
# output ['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange', 'grape']
fruits.sort()
fruits
# output ['apple', 'apple', 'banana', 'banana', 'grape', 'kiwi', 'orange', 'pear']

len(fruits)  # length of fruits array
# output 8

# loop and print each fruit
for fruit in fruits:
  print(fruit)
  
empty_set = set()

basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}
print(basket)                      # show that duplicates have been removed
# output {'orange', 'banana', 'pear', 'apple'}

# check if orange is in basket set
print('orange' in basket)
# output true

# convert a string to a set of letters - sets contains no duplicates
set_a = set('abcd')
set_b = set('bcde')

# the operations below returns new sets
# print letters in set_a but not in set_b - difference
print(set_a - set_b)
# output {'a'}

# print set letters that is in either set a or b - union
print(set_a | set_b)
# output {'a', 'c', 'e', 'b', 'd'}

# print letters that are in both set_a and set_b - intersection
print(set_a & set_b)
# output {'c', 'd', 'b'}

# print letters that are in set_a and set_b when the letters are found in a set but no the other set - symmetric_difference()
print(set_a ^ set_b)
# output {'a', 'e'}

# Creating dictionaries
dict1 = {'color': 'blue', 'shape': 'square', 'volume': 40}
dict2 = {'color': 'red', 'edges': 4, 'perimeter': 15}

# Creating new pairs and updating old ones
dict1['area'] = 25  # {'color': 'blue', 'shape': 'square', 'volume': 40, 'area': 25}
dict2['perimeter'] = 20  # {'color': 'red', 'edges': 4, 'perimeter': 20}

# Accessing values through keys - an KeyError will occur if the key does not exists
print(dict1['shape'])

# You can also use get, which doesn't cause an exception when the key is not found
dict1.get('false_key')  # returns None
dict1.get('false_key', "key not found")  # returns the custom message that you wrote

# Delete item key and return the value if the key does not exists a KeyError occurs
print(dict1.pop('volume'))

# Merging two dictionaries
dict1.update(dict2)  # if a key exists in both, it takes the value of the second dict
dict1  # {'color': 'red', 'shape': 'square', 'area': 25, 'edges': 4, 'perimeter': 20}

# Getting only the values, keys or both (can be used in loops)
dict1.values()  # dict_values(['red', 'square', 25, 4, 20])
dict1.keys()  # dict_keys(['color', 'shape', 'area', 'edges', 'perimeter'])
dict1.items()
# dict_items([('color', 'red'), ('shape', 'square'), ('area', 25), ('edges', 4), ('perimeter', 20)])

# create a shallow copy of dict1
dict3 = dict1.copy()
# dict3 = {'color': 'red', 'shape': 'square', 'area': 25, 'edges': 4, 'perimeter': 20}

Source: codefreelance.net

Python cheat sheet

Best Python Cheat Sheet PDF:
https://websitesetup.org/wp-content/uploads/2020/04/Python-Cheat-Sheet.pdf

Source: websitesetup.org

Python cheat sheet

print('Hello World') # print
string_name = "This is a string" # string
string_name[5:] # slicing returns "is a string"
integer_name = 4 # integer
float_name = 3.0 # float
list_name = ['a','b','cats','dogs', 1, 2.0] # list
list_name.append(3) # add to list
# list comprehension filters for int types from the previous list
list_comp = [x for x in list_name if type(x) is int]
# dictionary
dic = {"Bob":9766692343,"Alice":6123336678}
dic["Alice"] # returns 6123336678
dic_phone_numbers = dic.values() # returns list of values
dic_names = dic.keys() # returns list of keys
# class (cat object with 9 lives)
class Cat:
  def __init__(self,name):
    self.name = name
    self.lives = 9
    print(f"{name} is a cat!")
# recursive function (factorial example)
def factorial(x):
    if x == 1:
        return 1
    else:
        return (x * factorial(x-1))

Source: grepper.com

Cheat sheet python

>>> 2 + 3 * 6
20

Source: pythoncheatsheet.org

Cheat sheet python

>>> int(7.7) + 1
8

Source: pythoncheatsheet.org

Cheat sheet python

>>> str(-3.14)
'-3.14'

Source: pythoncheatsheet.org

Cheat sheet python

def foo():
    """
    This is a function docstring
    You can also use:
    ''' Function Docstring '''
    """

Source: pythoncheatsheet.org

Cheat sheet python

>>> spam = 'Hello'
>>> spam
'Hello'

Source: pythoncheatsheet.org

Cheat sheet python

>>> 'Alice' 'Bob'
'AliceBob'

Source: pythoncheatsheet.org

Cheat sheet python

>>> print('What is your name?')   # ask for their name
>>> myName = input()
>>> print('It is good to meet you, {}'.format(myName))
What is your name?
Al
It is good to meet you, Al

Source: pythoncheatsheet.org

Cheat sheet python

>>> len('hello')
5

Source: pythoncheatsheet.org

Cheat sheet python

# This is a comment

Source: pythoncheatsheet.org

Cheat sheet python

>>> _spam = 'Hello'

Source: pythoncheatsheet.org

Cheat sheet python

# This is a
# multiline comment

Source: pythoncheatsheet.org

Cheat sheet python

>>> a = [1, 2, 3]
>>> if a:
>>>     print("the list is not empty!")

Source: pythoncheatsheet.org

Cheat sheet python

a = 1  # initialization

Source: pythoncheatsheet.org

Cheat sheet python

>>> print('Hello world!')
Hello world!

Source: pythoncheatsheet.org

Cheat sheet python

>>> print('I am {} years old.'.format(str(29)))
I am 29 years old.

Source: pythoncheatsheet.org

Python Cheat Sheets

#A few cheat sheets related with python, data wrangling and data visualization. Even with a perfect understanding of python and its libraries

https://www.python-graph-gallery.com/cheat-sheets/

https://www.askpython.com/

Source: grepper.com

Comprehensive python cheat sheet

>>> product([0, 1], repeat=3)
[(0, 0, 0), (0, 0, 1), (0, 1, 0), (0, 1, 1), ..., (1, 1, 1)]

Source: gto76.github.io

Python cheat sheet

Awesome Python Cheatsheet!

Source: github.com

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