🔎 What is f = open()

This simply connects a variable in python to an external file (a text file in the same folder)

• From this point on, all we need to do is use f when we want to do things with the file
• We can use another variable name but f is easier for a programmer to remember

(connecting to the file)
   ⬇️
f = open("travel.txt","a")

🔎 What is "travel.txt"

You need to write the name of the file (including .txt)

• .txt tells python this is a text file
• This is the first of two things that go inside of the brackets

            (file name)
               ⬇️
f = open("travel.txt","a")

🔎 What does "a" do?

Python can access other files in one of three different modes

• Read (simply copying the content of the file into the python program)
• Write (replacing the content of the file with new content)
• Append (adding new content to the file - at the end)

In this lesson, we will just focus on appending to a file "a"

                 (append mode)
                      ⬇️
f = open("travel.txt","a")

🐍 Writing a destination to the travel file (1)

We will now allow the user to input a destination.

This will then be written to the file

• Create a variable called place
• Assign an input to the variable
• Use the prompt text "Enter a destination you would like to travel to: "

place = input("Enter a destination you would like to travel to: ")

🐍 Writing a destination to the travel file (2)

We will now take the user input and write it to the file

f.write(place)

🐍 Writing a destination to the travel file (3)

Let the user know that their destination has been successfully added!

print(f"Destination: {place} Added!")

🐍 Closing the connection to the file

It is really important to always close the connection to a file once you are finished with it.

This is because it is open in a particular mode e.g. append, however you might wish to open it later in another mode e.g. read

f.close()

🐍 Run the program

• Run the program three times
• Enter a different country each time

Enter a destination you would like to travel to: Spain
Destination Added!

Enter a destination you would like to travel to: France
Destination Added!

Enter a destination you would like to travel to: Portugal
Destination Added!

🔎 Now open the file travel.txt

Something isn't quite right!

SpainFrancePortugal

• Delete the text in the file
• Advance to the next slide to see how we fix this ➡️

🐍 Adding the new-line-character

Find this line of code

f.write(place)

Change it to this

f.write(place + "\n")

• ⬆️ This adds the new-line-character (\n) to the end of the text
• "\n" tells the computer to start a new line
• "\n" won't be displayed when you view the file
• However, it is still there!

🐍 Run and check it worked!

• Run the program three times again.
• Each time, type a travel destination
• The file should look like this!

Spain
France
Portugal

Don't forget to answer the questions at the bottom of the python file!

🐍 Creating the connection

• Create a connection to the file timetable.txt
• Make sure it is in append "a" mode
Click to see how this should look

f = open("timetable.txt","a")

🐍 Creating multiple inputs

Create variables and inputs (with suitable prompts) for the following:

• The day
• The lesson number
• The subject
• The teacher
Click to see how this should look

day = input("Enter the day of the lesson: ")
ln = input("Enter the lesson number: ")
subject = input("Enter the subject: ")
teacher = input("Enter the teacher: ")

🐍 Concatenate your inputs

• We will now join the inputs together
• This is called concatenation
• We use the + symbol to concatenate

day + " - Week A : Lesson " +  ln + " : " + subject + " : " + teacher 

• We will also add a new-line-character to the end

day + " - Week A : Lesson " +  ln + " : " + subject + " : " + teacher + "\n"

• We will assign it to a variable

entry = day + " - Week A : Lesson " +  ln + " : " + subject + " : " + teacher + "\n"

🐍 Write the concatenated input to the file

• Use the f.write() function to effectively write the information
Click to see how this should look

f.write(entry)

🐍 Notify the user

Let the user know that their lesson has been successfully added!

print(f"{entry} --- added!")

🐍 Close the connection

Make sure you close the connection to the file

f.close()

🐍 Run the program to check it works!

• Run the program to see if it works:
• Enter your lessons for Monday A!
• Open the file to see if it is successfully written to


• Answer the questions at the bottom of the code file

🐍 Activity 3 - Extension

• See if you can get the program to run in a big while loop
• Each time they are asked to type (1) To enter a new thing or (2) to exit
• This will allow them to keep adding new things without having to re-run the program

while True:
    print("Enter (1) to enter another track (2) to exit the program")
    choice = input("➡️️ ")
    
    if choice == "1":
        [[[The lines of code for your file writing app]]]
    
    elif choice == "2":
        print("Program Exited - Goodbye 😃")
        break
    
    else:
        print("Invalid choice")