Skip to content

Latest commit

 

History

History
249 lines (241 loc) · 7.02 KB

recapGuide.md

File metadata and controls

249 lines (241 loc) · 7.02 KB

Welcome to Recap Guide

These small notes are just for a quick recap of python functions, operators, data types, and lot more.

Print function

Always use String in Double Quotes and all integers, boolean, floats and variables without quotes.

print("Hello World")

Python Interpreter as Calculator

We can use the python interpreter like calculator without any functions or variables, just open the terminal and type python and get started.

Comments in Python

We can add single line comments by using #.
We can add multiline comments using ''' or """ or ```

Escape Sequence Characters

  • For next line we use \n
  • If you want to print a quote in String then we need to use \
  • For tabs use \t
print("Akshay is \n Good Boy \t and an Intelligent person")

Variables, type function and typecasting

Storage boxes in python which is used to store some data or value either statically or dynamically.

  • There is a function called type() which is used to print the type of the variable or value.
var1 = "Akshay Bengani"
var2 = 123
var3 = 23.4
var4 = True

type(var1)
type(var2)
type(var3)
type(var4)
  • In case when you need to convert type of a variable then we need to use these special functions used to typecast the entire variable.
var1 = "54"
var2 = "20"
str()
int()
float()
bool()
print(int(var1) + int(var2))
  • Print something multiple times
print(100 * "Hello this is Akshay")

Input function

To get a user input we have a function called input()

print("Enter a number")
var1 = input()
print("You entered ", int(var1) + 10)

String Datatypes and Functions

  • To get a particular character of a string use [] with the index position.
var1 = "Akshay is a Good boy"
print(var1[2])
  • String Slicing is used to get a particular slice of a string or a part of a string.
  • In case if you entered the ending number more then the length then there is no error it just print the maximum as he can.
var1 = "Akshay is a Good boy"
print(var1[2:6])
print(var1[2:42])
  • To get a length of a string use len() function
var1 = "Akshay is a Good Boy"
print(len(var1))
  • In case if I need to skip the characters in a string we use the :: for slicing.
  • To skip 1 character from a part of string or whole string use this ::
var1 = "Akshay is a Good Boy"
print(var1[0:20:2])
print(var1[0::2])
print(var1[:20:2])
print(var1[::2])
  • Negative indexes in String, this is used when you need to read the string from the end, as such all the string operations will be done reverse from the end.
var1 = "Akshay is a Good Boy"
print(var1[-1])
print(var2[-3])
print(-4:-2)
print()
  • Alphanumeric functions check that the string contains anything else then characters and numbers, it checks for symbols and spaces.
var1 = "Akshay is a good boy"
print(var1.isalnum())
print(var1.isalpha())
  • Check that the string end with a specific value or not
var1 = "Akshay is a Good Boy"
print(var1.endswith("Boy"))
  • Count a specific character or word in the whole string use the count() function.
var1 = "Akshay is a Good Boy"
print(var1.count('o'))
  • To Capitalize the 1st character of a String we use the function capitalize()
var1 = "akshay is a good boy"
print(var1.capitalize())
  • To find something position in a String we use the function find() this will return the starting position of the search item.
var1 = "Akshay is a Good Boy"
print(var1.find("is"))
  • To replace something in string with something use the function replace()
var1 = "Akshay is a Good boy"
print(var1.replace('is','are'))
  • In case if you need more inbuilt String functions Google it.

List and List Functions

  • To create a list we use [] and store it in a variable.
list1 = ['Apple','Vim Bar',12,34.55,True,'Orange']
print(list1[2])
print(list1)
  • To sort a list of numbers in ascending or decending order.
numbers = [43,564,353,34,6,3,75,35,5]
# To sort in ascd order
numbers.sort()
# To sort in decd order just reverse the sorted one
numbers.reverse()
print(numbers)
  • List Slicing
numbers = [43,564,353,34,6,3,75,35,5]
print(numbers[0:5])
print(numbers[:5])
print(numbers[2:])
print(numbers)
  • Extended Slicing
numbers = [43,564,353,34,6,3,75,35,5]
print(numbers[::1])
print(numbers[::2])

print(numbers[::-1])
print(numbers[::-2])
  • To add a value in a list use the function append()
numbers = []
numbers.append(21)
numbers.append(22)
numbers.append(23)
numbers.append(24)
print(numbers)
  • To add a value in a list at a specific position use the function insert()
numbers = []
numbers.insert(0,53)
numbers.insert(1,53)
numbers.insert(13,53)
  • To remove a value from a list use the function remove(), it will remove the 1st occurance of the value.
numbers = [43,564,353,34,6,3,75,35,5]
numbers.remove(564)
  • To remove the last value of the list then use the pop() function.
numbers = [43,564,353,34,6,3,75,35,5]
numbers.pop()

Tuples and Tuple Functions

  • Tuples is used to create Immutable list which cannot be changed.
  • Tuples use () and list uses [].
  • You cannot change a value of a Tuple
  • But we can add values in a tuple using append not insert function.
  • When we need to create a single value tuple we need to add a , after the 1st value.
tp = (1,)

Dictionaries and Dictionary Functions

  • Dictionary is nothing but key value pairs.
d2 = {'Akshay':'Chicken','Aastha':'Roti','Shivank':'Patties'}
print(d2['Akshay'])
print(d2['Aastha'])
  • We can create nested Dictionaries within Dictionaries.
d2 = {'Akshay':'Chicken','Aastha':'Roti','Shivank':'Patties','Kirti':{'B':'Poha','L':'Bhindi','D':'Paneer'},'Meenal':'Aalu'}
print(d2['Kirti']['L'])
  • In case you need to add data in Dict
d2['Ankit'] = "Junk Food"
  • To delete an entry from dict
d2['Ankit'] = "Junk Food"
del d2['Ankit']
  • In case you need to make a copy of a dictionary you need to use the copy function because when we assign dictionary like variables it returns the pointer as such you should use copy() function for making a fresh new copy of the Dict.
d2 = {'Akshay':'Chicken','Aastha':'Roti','Shivank':'Patties'}
d3 = d2.copy()
print(d3)
  • To update a value in Dict use the update() function
d2 = {'Akshay':'Chicken','Aastha':'Roti','Shivank':'Patties'}
d2.update({'Akshay':'Tandoor'})
  • To get keys of the dict
d2 = {'Akshay':'Chicken','Aastha':'Roti','Shivank':'Patties'}
print(d2.keys())

Set and its functions

  • Set is a data structure in Python which is used to store unique values, and it can implement all kind of mathematical operations on set.
s = set()
print(type(s))
l = [1, 2, 3, 4]
s_from_list = set(l)
print(s_from_list)
print(type(s_from_list))
s.add(1)
s.add(2)
s.remove(2)
s1 = {4, 6}
print(s.isdisjoint(s1))

IF Else and Elif

  • I am skipping this part because its very easy and nothing to recap.