if __name__ == '__main__': # If file is not imported, this will be executed main()

$ python3

$ pip3 install <package-name>

$ python3 <filename>.py

$ time python3 <filename>.py

import <filename>

input("Input: ")

print("Output")

number = 0 org = "GitHub"

x,y = 0,1 if x < y: print("x is less than y") else: print("x is not less than y")

for i in range(5): print(i)

i=0 while(i < 10): print("{} is less than 10".format(i)) i += 1

>>> foo = 'world' >>> 'Hello %s' % foo 'Hello world'

>>> foo = 'James' >>> bar = 'Nancy' >>> 'Hi, my name is %s and this is %s' % (foo, bar) 'Hi, my name is James and this is Nancy'

>>> dict = { "name": "Mike", "country": "Canada" } >>> 'I am %(name)s and I am from %(country)s' % dict 'I am Mike and I am from Canada'

>>> 'Hello {}'.format('world') 'Hello world'

>>> 'Hi {name}, your total is ${total}'.format(name='Bob', total=5.50) 'Hi Bob, your total is $5.5'

>>> a = 5 >>> b = 10 >>> f'Five plus ten is {a + b} and not {2 * (a + b)}.' 'Five plus ten is 15 and not 30.'

def sum(a, b) : return a + b def subtract(a, b) : return a - b def getPerson(name, age) : person = { "name": name, "age": age } return person

a = 20 b = 50 c = sum(a, b) d = sum(b, 50) e = subtract(b, a) p = getPerson("Joe", 25) # OUTPUT: print( "Sum - {} plus {}: {}" . format( a, b, c ) ) # Sum - 20 plus 50: 70 print( "Sum - {} plus 50: {}" . format( b, d ) ) # Sum - 50 plus 50: 100 print( "Subtraction - {} minus {}: {}" . format( b, a, e ) ) # Subtraction - 50 minus 20: 30 print( "Person - {}" . format( p ) ) # Person - {'name': 'Joe', 'age': 75}

def yell(text): # Define function yell return text.upper() + '!' >>> bark = yell # Declare an object "bark" that contains the function "yell" >>> bark('woof') # You could now execute the "yell" function object by calling bark 'WOOF!'

def speak(text): # Define function speak def wisper(t): # Function wisper does not exist outside speak return t.lower() + '...' return wisper(text) >>> speak('Hello, World') 'hello, world...'

>>> add = lambda x, y: x + y >>> add(5, 3) 8

def add(x, y): return x + y >>> add(5, 3) 8

# These are all inplace operations returns a None value <list>.append(<ele>) # Add an element to the end of the list <list>.sort() # Sorts the given list <list>.pop([<ele>]) # Removes the last element if no argument else removes the element at the index given <list>.clear() # Makes it an empty list <list>.insert(<index>, <ele>) # Adds the element before the index <list>.extend(<iterator>) <list>.reverse() # Reverse a given list

# These are not inplace operations and has a return value <list>.copy() # Makes a shallow copy of the list <list>.index(<ele>) # Returns the index of the given element <list>.count(<ele>) # Returns the number of occurrences of the element

<dict> = {'Google':100, 'Facebook':80, 'Apple':90} <dict>['Amazon'] = 85 # Adding a key along with the value # Accessing the dictionary for key in <dict>: print("{key} -> {x}".format(key=key, x=<dict>[key])) <dict>.keys() # Print all the keys <dict>.values() # Print all the values len(<dict>) # Find the length of the dictionary <dict>.pop(<key>) # Removes the item with the specified key name <dict>.copy() # Make a copy of a dictionary

this_tuple = ('books', 'pen', 'paper') # Defined a tuple # Accessing Tuple Items print(this_tuple[2]) # paper

desk_tuple = ("pen stand", "plant", "marker") desk_list = list(desk_tuple) desk_list[2] = "highlighter" desk_tuple = tuple(desk_list) print(desk_tuple[2]) # highlighter

this_tuple = ("Python",) print(type(this_tuple)) # tuple # NOT a tuple this_tuple = ("Python") print(type(this_tuple)) # str

this_tuple = ('books', 'pen', 'paper') del this_tuple print(this_tuple) # ERROR: this_tuple is not defined ## Third party libraries

import pandas as pd <dataframe>.head([<n>]) # Display the first n rows of the Dataframe, default value is 5 rows <dataframe>.tail([<n>]) # Display the last n rows of the Dataframe, default value is 5 rows <dataframe>.info() # Gives some information like, row and column datatypes, non-null count, and memory usage <dataframe>.describe() # Provides some descriptive statistics about the numerical rows in the dataframe

#Series sr = pd.Series([100, 200, 300, 400], index=["red", "green", "yello", "black"]) print(sr) print(sr.values) print(sr.index) #A series class has a structure that allows you to give values in one-dimensional arrays an index that corresponds to each value.

#DataFrame values = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] index = ['one', 'two', 'three'] columns = ['A', 'B', 'C'] df = pd.DataFrame(values, index=index, columns=columns) print(df) print(df.index) print(df.columns) print(df.values) #DataFrame passes a two-dimensional list as a parameter. Compared to a series, a data frame is added up to columns, consisting of columns, indexes, and values.

import nltk # Before trying any function download the word list nltk.download('punkt') nltk.download('averaged_perceptron_tagger')

a = 10 * (1/0) # Throws division by zero exception and terminate the program # Traceback (most recent call last): File "", line 1, in a = 10 * (1/0) # ZeroDivisionError: division by zero # Updated Program - Valid - Try: Except: Finally b = 10 try: a = 10 * (1/b) print( "a = {}" .format( a ) ) except: print( "Caught divide by zero - while getting a" ) print( "Execute on error - b must be non-zero value" ) finally: print( "Execute Always - normal and exceptional flow" ) # OUTPUT a = 1.0 Execute Always - normal and exceptional flow ## Updated Program - Error - Try: Except: Finally b = 0 try: a = 10 * (1/b) print( "a = {}" .format( a ) ) except: print( "Caught divide by zero - while getting a" ) print( "Execute on error - b must be non-zero value" ) else: print( "Alternate to exceptional flow" ) # Output Caught divide by zero - while getting a Execute on error - b must be non-zero value Execute Always - normal and exceptional flow

from collections import Counter def anagram(first, second): return Counter(first) == Counter(second) anagram("abcd3", "3acdb") # True

import sys variable = 30 print(sys.getsizeof(variable)) # 24

n = 2 s ="Programming" print(s * n) # ProgrammingProgramming

def chunk(list, size): return [list[i:i+size] for i in range(0,len(list), size)]

def get_vowels(string): return [each for each in string if each in 'aeiou'] get_vowels('foobar') # ['o', 'o', 'a'] get_vowels('gym') # []

def lengthOfLastWord(self, s: str) -> int: if(s.split()): lst=s.split() last=lst[-1] return len(last) return 0

def isPalindrome(self, s: str) -> bool: s = [ x.lower() for x in s if x.isalnum() ] return s == s[::-1]

def toLowerCase(self, str): """  :type str: str  :rtype: str  """ return str.lower()

def countNegatives(self, grid: List[List[int]]) -> int: count = 0 for num in grid: for n in num: if n < 0: count += 1 return count

def write_to_file(filename, content): try: with open(filename, "w+") as f: f.write(content) print("Written to file successfully.") except Exception as e: print("Failed to write to file with error: ") print(e)

import statistics def median(arr): print(statistics.median(arr))

def find_Evenodd(num): if(num%2==0): print(num," Is an even") else: print(num," is an odd")

def isPalindrome(s): if (s == s[::-1]): return "yes" else: return "no"