Nina Diana

Nina Diana

1567559458

5 Best Python Switch Case Example

Introduction

A switch case statement in a computer programming language is a powerful tool that gives the programmer total control over the flow of the program according to the outcomes of an expression or a variable.

Switch cases are particularly used to execute a different block of codes in relation o the results of expression during the program run time.

The program takes a certain course if the result is a certain value and another course if the result is another value and so on and so forth.

Let me begin by showing you how a switch case statement functions in Java so that you have a clue of what to expect in the python switch case statement, although it could be different in the way they have implemented, the concept remains the same.

I will later take you through the 5 best Python switch case example.

Java switch case demo of how to switch between months of the year and provide a default result if no match is found in the switch statement.

public static void switch_demo(String[] args) {

int month = 7;

String monthString;

switch (month) {

case 1:  monthString = "January";

break;

case 2:  monthString = "February";

break;

case 3:  monthString = "March";

break;

case 4:  monthString = "April";

break;

case 5:  monthString = "May";

break;

case 6:  monthString = "June";

break;

case 7:  monthString = "July";

break;

case 8:  monthString = "August";

break;

case 9:  monthString = "September";

break;

case 10: monthString = "October";

break;

case 11: monthString = "November";

break;

case 12: monthString = "December";

break;

default: monthString = "Invalid month";

break;

}

System.out.println(monthString);

}

Let’s break down the above switch case statement:

Step 1: The compiler first generates a jump table for the switch statement

Step 2: The switch statement evaluates the variable or the expression only once.

Step 3: The switch statement looks upon the evaluated result and makes a decision based on the result on which block of code to execute.

The default code will be executed in case there is no match found.

In the case example above, if the default block of code is executed the result will be “invalid month”, but since the month variable is initialized as 7, the output will be ‘July’.

Guido Van Rossum a Python developer believed in a simple programming language that could bypass the system vulnerabilities and hitches found in other programming languages, he wanted to create a simple syntax with more sophisticated syntactic phrases.
He never imagined that today, Python programming language could be the programming language to look up to when it comes to the standard language for designing scientific machine learning applications.

Switch case examples in Python

Python doesn’t have built-in switch statements like you could find programming languages likePHP and Java does, instead, as a Python programmer you could be tempted to use if-else-if blocks, but switch cases are efficient to use because of jump table than the if-else-if ladder.

The reason for this is, instead of evaluating each condition in a sequential manner, it looks at the evaluated expression or variable and jumps directly to the relevant branch of code to execute.

Switch using an if-else-if ladder to find the surface area, literal area, and volume of a cylinder

def switch():

r = int(input("Enter Radius : "))

h = int(input("Enter Height : "))

print("Press 1 for Surface Area \npress 2 for Literal Area \npress 3 for Volume \n")

option = int(input("your option : "))

if option == 1:

result = 2*3.17*r*(r+h)

print("\nSurface Area Of Cylinder = ",result)

elif option == 2:

result = 2 * 3.17 * r * h

print("Literal Area Of Cylinder = ", result)

elif option == 3:

result = 3.17*r*r*h

print("Volume Of Cylinder = ", result)

else:

print("Incorrect option")

switch()

Explanation: In the example above, if the option is 1, the surface area of a cylinder is calculated if the option is 2, the literal surface area is calculated and finally option 3, the volume of the cylinder is calculated.

Switch case statement using class to convert literal to string ‘month’

class PythonSwitchStatement:

def switch(self, month):

default = "Invalid month"

return getattr(self, 'case_' + str(month), lambda: default)()

def case_1(self):

return "January"

def case_2(self):

return "February"

def case_3(self):

return "March"

def case_4(self):

return "April"

def case_5(self):

return "May"

def case_6(self):

return "June"

def case_7(self):

return "July"

def case_8(self):

return "August"

def case_9(self):

return "September"

def case_10(self):

return "October"

def case_11(self):

return "November"

def case_12(self):

return "December"

s = PythonSwitchStatement()

print(s.switch(1))

print(s.switch(3))

print(s.switch(13))

The output will be:

___________________

January

March

Invalid month

___________________

Explanation: First, create a class called PythonSwitchStatement to define a switch() method. It also defines other functions for specific different cases.

The switch() method takes an argument ‘month’ and converts it to string then appends it to the case literal and then passes it to the getattr() method, which then returns the matching function available in the class.

If it doesn’t find a match, the getattr() method will return lambda function as the default.

Dictionary mapping replacement

# Function to convert number into string


# Switcher is dictionary data type here

def numbers_to_strings(argument):

switcher = {

0: "zero",

1: "one",

2: "two",

}

# get() method of dictionary data type returns

# value of passed argument if it is present

# in dictionary otherwise the second argument will

# be assigned as the default value of the passed argument

return switcher.get(argument, "nothing")

# Driver program

if __name__ == "__main__":

argument=0

print numbers_to_strings(argument)

xample using Dictionary mapping for functions by Switcher

def one():

return "January"

def two():

return "February"

def three():

return "March"

def four():

return "April"

def five():

return "May"

def six():

return "June"

def seven():

return "July"

def eight():

return "August"

def nine():

return "September"

def ten():

return "October"

def eleven():

return "November"

def twelve():

return "December"

def numbers_to_months(argument):

switcher = {

1: one,

2: two,

3: three,

4: four,

5: five,

6: six,

7: seven,

8: eight,

9: nine,

10: ten,

11: eleven,

12: twelve

}

# Get the function from switcher dictionary

func = switcher.get(argument, lambda: "Invalid month")

# Execute the function

print func()

Example using a dictionary mapping to return value

b ={

'a' : 122,

'b' : 123,

'c' : 124,

'd' : 125

}

# take user input

inp = input('input a character : ')

# -1 is the default value if there are no keys that match the input

print('The result for inp is : ', b.get(inp, -1))

Output:

Using dictionary mapping to switch the days of the week

def week(i):

switcher={

0:'Sunday',

1:'Monday',

2:'Tuesday',

3:'Wednesday',

4:'Thursday',

5:'Friday',

6:'Saturday'

}

return switcher.get(i, "Invalid day of the week")

Then make calls to week() with different values to find out the day of the week.

i.e week(2), the output will be Tuesday, week(4), the output will be Thursday while week(5.5)will output “Invalid day of the week”

Conclusion

Python does not have an in-built switch-case construct, but you can use dictionary mapping instead in place of switch case.

Python developer did not include the switch-case construct for a good reason.

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5 Best Python Switch Case Example
Ray  Patel

Ray Patel

1619518440

top 30 Python Tips and Tricks for Beginners

Welcome to my Blog , In this article, you are going to learn the top 10 python tips and tricks.

1) swap two numbers.

2) Reversing a string in Python.

3) Create a single string from all the elements in list.

4) Chaining Of Comparison Operators.

5) Print The File Path Of Imported Modules.

6) Return Multiple Values From Functions.

7) Find The Most Frequent Value In A List.

8) Check The Memory Usage Of An Object.

#python #python hacks tricks #python learning tips #python programming tricks #python tips #python tips and tricks #python tips and tricks advanced #python tips and tricks for beginners #python tips tricks and techniques #python tutorial #tips and tricks in python #tips to learn python #top 30 python tips and tricks for beginners

Ray  Patel

Ray Patel

1619510796

Lambda, Map, Filter functions in python

Welcome to my Blog, In this article, we will learn python lambda function, Map function, and filter function.

Lambda function in python: Lambda is a one line anonymous function and lambda takes any number of arguments but can only have one expression and python lambda syntax is

Syntax: x = lambda arguments : expression

Now i will show you some python lambda function examples:

#python #anonymous function python #filter function in python #lambda #lambda python 3 #map python #python filter #python filter lambda #python lambda #python lambda examples #python map

Art  Lind

Art Lind

1602968400

Python Tricks Every Developer Should Know

Python is awesome, it’s one of the easiest languages with simple and intuitive syntax but wait, have you ever thought that there might ways to write your python code simpler?

In this tutorial, you’re going to learn a variety of Python tricks that you can use to write your Python code in a more readable and efficient way like a pro.

Let’s get started

Swapping value in Python

Instead of creating a temporary variable to hold the value of the one while swapping, you can do this instead

>>> FirstName = "kalebu"
>>> LastName = "Jordan"
>>> FirstName, LastName = LastName, FirstName 
>>> print(FirstName, LastName)
('Jordan', 'kalebu')

#python #python-programming #python3 #python-tutorials #learn-python #python-tips #python-skills #python-development

Art  Lind

Art Lind

1602666000

How to Remove all Duplicate Files on your Drive via Python

Today you’re going to learn how to use Python programming in a way that can ultimately save a lot of space on your drive by removing all the duplicates.

Intro

In many situations you may find yourself having duplicates files on your disk and but when it comes to tracking and checking them manually it can tedious.

Heres a solution

Instead of tracking throughout your disk to see if there is a duplicate, you can automate the process using coding, by writing a program to recursively track through the disk and remove all the found duplicates and that’s what this article is about.

But How do we do it?

If we were to read the whole file and then compare it to the rest of the files recursively through the given directory it will take a very long time, then how do we do it?

The answer is hashing, with hashing can generate a given string of letters and numbers which act as the identity of a given file and if we find any other file with the same identity we gonna delete it.

There’s a variety of hashing algorithms out there such as

  • md5
  • sha1
  • sha224, sha256, sha384 and sha512

#python-programming #python-tutorials #learn-python #python-project #python3 #python #python-skills #python-tips

How To Compare Tesla and Ford Company By Using Magic Methods in Python

Magic Methods are the special methods which gives us the ability to access built in syntactical features such as ‘<’, ‘>’, ‘==’, ‘+’ etc…

You must have worked with such methods without knowing them to be as magic methods. Magic methods can be identified with their names which start with __ and ends with __ like init, call, str etc. These methods are also called Dunder Methods, because of their name starting and ending with Double Underscore (Dunder).

Now there are a number of such special methods, which you might have come across too, in Python. We will just be taking an example of a few of them to understand how they work and how we can use them.

1. init

class AnyClass:
    def __init__():
        print("Init called on its own")
obj = AnyClass()

The first example is _init, _and as the name suggests, it is used for initializing objects. Init method is called on its own, ie. whenever an object is created for the class, the init method is called on its own.

The output of the above code will be given below. Note how we did not call the init method and it got invoked as we created an object for class AnyClass.

Init called on its own

2. add

Let’s move to some other example, add gives us the ability to access the built in syntax feature of the character +. Let’s see how,

class AnyClass:
    def __init__(self, var):
        self.some_var = var
    def __add__(self, other_obj):
        print("Calling the add method")
        return self.some_var + other_obj.some_var
obj1 = AnyClass(5)
obj2 = AnyClass(6)
obj1 + obj2

#python3 #python #python-programming #python-web-development #python-tutorials #python-top-story #python-tips #learn-python