Strings are the primary way that we interact with non-numerical data in programming, and the `str` type in Python provides us with a lot of powerful methods to make working with string data easier. In this hands-on lab, we’ll be creating a script that can take a user-provided message and perform various actions on it before printing out those new results.
To feel comfortable completing this lab you’ll want to know how to do the following:
* Utilize methods on the `str` class. Watch the “Using String Methods” from the Certified Entry-Level Python Programmer Certification course.
* Working with list literals. Watch the “Lists” video from the Certified Entry-Level Python Programmer Certification course.
* Using List functions and methods. Watch the “List Functions and Methods” video from the Certified Entry-Level Python Programmer Certification course.
Learning Objectives
Successfully complete this lab by achieving the following learning objectives:
- Create the variations.py Script, Make It Executable with python3.7, and Accept User Input
For
variations.py, we’re going to place it in our home directory (~) and we want to make sure that we can run it directly. To keep from being completely tied to the path of ourpython3.7binary,
we want to set up our shebang properly.Let’s create the file and set the shebang:
~/variations.py
#!/usr/bin/env python3.7 # Python implementation hereWith the file created, we need to also make sure that it’s executable and we can do this using
chmod:$ chmod u+x ~/variations.pyNext, we’ll prompt the user for a message and store it off in a variable.
~/variations.py
#!/usr/bin/env python3.7 message = input("Enter a message: ")Now if we run the script (
./variations.py) it should prompt us for a message, and then exit without any errors.- Print the Lowercase, Uppercase, Title Case, and Capitalized Versions of the User’s Input
Now that we have the
messagevariable, we’re going to print a few different things to the screen:- The lowercase version using
str.lower - The uppercase version using
str.upper - The title case version using
str.title - The capitalized version using
str.capitalize
Let’s use each of these methods combined with the
printfunction:~/variations.py
#!/usr/bin/env python3.7 message = input("Enter a message: ") print("Lowercase:", message.lower()) print("Uppercase:", message.upper()) print("Capitalized:", message.capitalize()) print("Title Case:", message.title())Now we can run the script to make sure that what we’ve written up to this point is working properly:
$ ./variations.py Enter a message: This Is My Message Lowercase: this is my message Uppercase: THIS IS MY MESSAGE Capitalized: This is my message Title Case: This Is My Message- The lowercase version using
- Separate the String and Present the Individual Words as a List
For the remaining requirements of our script, we need to work with the individual words. Because of this, we’re going to store the words off as a new variable,
words. We can get the words by using thestr.splitmethod. After we’ve separated the message into words, let’s also print them out:~/variations.py
#!/usr/bin/env python3.7 message = input("Enter a message: ") print("Lowercase:", message.lower()) print("Uppercase:", message.upper()) print("Capitalized:", message.capitalize()) print("Title Case:", message.title()) words = message.split() print("Words:", words)Here’s the script running so far:
$ ./variations.py Enter a message: This is a test Message! Lowercase: this is a test message! Uppercase: THIS IS A TEST MESSAGE! Capitalized: This is a test message! Title Case: This Is A Test Message! Words: ['This', 'is', 'a','test','Message!']- Print the Alphabetic First and Last Words from the User’s Input
We’re going to sort the words in the
wordslist alphabetically and save the new list tosorted_wordsby using thesortedbuilt-in function. Lastly, we’ll print the alphabetic first and last words. Let’s do this by indexing to0and-1.~/variations.py
#!/usr/bin/env python3.7 message = input("Enter a message: ") print("Lowercase:", message.lower()) print("Uppercase:", message.upper()) print("Capitalized:", message.capitalize()) print("Title Case:", message.title()) words = message.split() print("Words:", words) sorted_words = sorted(words) print("Alphabetic First Word:", sorted_words[0]) print("Alphabetic Last Word:", sorted_words[-1])Here’s the final script running:
$ ./variations.py Enter a message: This is a test message! Lowercase: this is a test message! Uppercase: THIS IS A TEST MESSAGE! Capitalized: This is a test message! Title Case: This Is A Test Message! Words: ['This', 'is', 'a','test','message!'] Alphabetic First Word: This Alphabetic Last Word: test
