   # Programming blog posts

## Introduction to Principal Component Analysis (PCA) in Python  ## Introduction to Principal Component Analysis (PCA) in Python

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Introduction to Principal Component Analysis (PCA)...

Python is no longer an unfamiliar word for profess... Read More

## Top 12 Python Packages for Machine Learning

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Top 12 Python Packages for Machine Learning

Lovers of vintage movies would have definitely hea... Read More

## What Is Memoization in Python

The term memoization gets its name from the Latin word memorandum meaning — ‘to be remembered’. Donald Michie, a British researcher in AI, introduced the term in the year 1968. It may look like a misspelling of the word memorization, but it comprises recording a value to look upon the function later. Above all, it is often a crucial technique in solving problems using Dynamic Programming.Definition of Memoization Memoization is an efficient software optimization technique used to speed up programs. It allows you to optimize a python function by catching its output based on the supplied input parameters. Memoization ensures that a method runs for the same input only once. Moreover, it keeps the output records for the given set of inputs in a hash map. That means, when you memorize a function, it will only compute the output once for every set of parameters called-with. Fibonacci sequence  A Fibonacci sequence is a series where each term is the sum of the preceding two terms. It plays a vital role in testing the memorization decorator recursively. We begin by defining the python function that calculates the nth Fibonacci number.  Program to find Fibonacci Series using recursive functions.def fibonacci(n):      if (n
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What Is Memoization in Python

The term memoization gets its name from the Latin ... Read More

## What are Membership Operators in Python

The membership operators are, as the name explains, used to verify a value membership. The operators are used to figure out if there are two forms of value as a part of a sequence, such as string or list membership operators: in and not in. To check whether two variables point to the same location or not, identity operators are used. Two forms of identity operators are is and is not. In general, operators are used to work on Python values and variables. These are regular symbols used for logical and arithmetical operations.Identity Operators: The Python identity operators are used to figure out whether a value is of a certain class or type. Typically, they are used for evaluating the type of information in a given variable. For example, to make sure you work with the variable type, you can combine identity operators with the built-in type() function. Python’s two identity operators are (is, is not).is: When evaluated, is Operator in Python returns true if the variables point to the same variable on either side of the operator and return false otherwise. Example 1: x = 5  if (type(x) is int):  print(“true”)  else:  print(“false”) Output: true Example 2: x =6  if(type(x) is int):  print("true")  else:  print("false") Output: true Example 3: list1 = [9, 8, 7, ‘i’]  list2 = list1  if list1 is list2:  print(“True”)  else:  print(“False”) Output: True The output here is true because list2 also refers to a list1 referenced by the variable list1. We may also use the is operator to verify if two python objects of the same type have other functions such as the type() function. is not: The operator ‘is not’ is the exact opposite of ‘is operator’ in Python. When evaluated, the operator returns false if the variables point to the same object on either side of the operator and return true otherwise. Example 1: x = 5.2  if (type(x) is not int):  print(“true”)  else:  print(“false”) Output: true Example 2: x =7.2  if(type(x) is not int):  print("true")  else:  print("false") Output: true Example 3: new_list = [9,8,7, 'i']  new_tuple = (9,8,7, 'i')  type(my_new_tuple)  if type(my_new_list) is not type(my_new_tuple):      print('True!, They are not of the same type')  else:      print("False, They are the same type") Output: True!, They are not of the same type Since the tuple and the list are not the same and the operator does not check their inequality, it returns True. Let us see a combined example of “is” and “is not”. Example: x = "identity operator"  if (type(x) is str):       print ("This is a string")   else:       print ("This is not a string")   y=987  if (type(y) is not str):       print ("This is a string")   else:       print ("This is not a string") Output: This is a string  This is not string Declare the value for variable x and y. Use the operator “is” to check if the value of x is the same as y. Next, we use the operator “is not” to check if the value of x is not the same as y. Example 2: a1 = 10  b1 = 10  a2 = ‘PythonProgramming’  b2 = ‘Programming’  a3 = [1,2,6]  b3 = [1,2,3]  print(a1 is not b1)  print(a2 is b2)  print(a3 is b3) Output: True  False  False Membership Operators: These operators evaluate membership in lists, sequences, or tuples in one sequence. In Python, there are two membership operators. (in, not in). It displays the result in the given sequence or string centred on the present variable.Membership Operators as a whole comprise a number of different operators. in Operator: It tests whether or not the value is present in the data sequence. It analyses the true value if the component is in the series and the false value if the component is not present.  Example 1: list1 = ['Aman', 'Bhuvan', 'Ashok', 'Vijay', 'Anil']  if 'Aman' in list1: print('Name Aman exists in list1') Output: Name Aman exists in list1 Example 2: list1=[1,2,4,5]  list2=[6,7,9]  for item in list1:  if item in list2:  print("overlapping")      else:  print("not overlapping") Output: not overlapping Example 3: new_list = [1,2,3,'a']  # loop around the list  for i in new_list:      print(i) Output: 1  2  3  a The in operator allows the variable i to refer to every element in the list iterated by the for loop. You have to think that the operator is used to check whether or not an element is present in a sequence, but what exactly happens? Well, when used in various ways, in a loop and in a conditional statement like if statement, the operator behaves differently. Let us remove the in operator in the example and modify it. Example: def overlapping(list1,list2):  c=0  d=0  for i in list1:  c+=1  for i in list2:  d+=1  for i in range(0,c):  for j in range(0,d):  if(list1[i]==list2[j]):  return1  return 0  list1=[1,2,3,4,5]  list2=[6,7,8,9]  if(overlapping(list1,list2)):  print("overlapping")  else:  print("not overlapping")  Output: not overlapping not in Operator: This operator verifies that a value is not present in a sequence. This is exactly contrary to the in operator. It evaluates to true when the element is not found or missing from the sequence and returns false when the element is found in the data sequence. The searchable element is the left operand and the right operand is the sequence in which it is searched. Example 1: x = 'Hello world'  y = {1:'a',2:'b'}  print('H' in x)  print('hello' not in x)  print(1 in y)  print('a' in y) Output: True  True  True  False Example 2: list=[10, 20, 30, 40, 50];  if( x not in list):  print("x is NOT present in the given list")  else:  print("x is present in the given list")  if( y in list):  print("y is present in the given list")  else:  print("y is NOT present in the given list") Output: x is NOT present in the given list  y is present in the given listExample 3: my_new_list = [1,2,3, 'a']  event = 'Studytonight'  if event not in my_new_list:      print('True') Output: True event not in my_new_list returns the negation of the in operator. The if condition checks if the special variable is included in the list or not. Since the special element isn’t in the list, it will return true. Example 4: list_one = [1, 2, 3]  list_two = [1, 2, 3]  list_one is not list_two Output: True This is because the lists apply to different objects in different memory locations.Conclusion: Identity and membership operators are useful to verify certain elements in a series of data and to verify the data identity respectively. Identity operators can be used with the type() function to check if a variable is of a certain type or class prior to any operation.
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What are Membership Operators in Python

The membership operators are, as the name explains... Read More