Activity: More file Input/Output (IO)

Create a file demo-files.py and save it to your CS100/ch5 directory. In that same directory, download and save the following text file if.txt.

1. Write code that will read in the text file and print out every line.

2. Write code that will count the total number of lines in the file, and output the number.

3. Use a dictionary to count how many times each word appears. Print the words that have been used more than 5 times.

4. Ask the user for a word to find and a word to replace it with. Read the if.txt file, and write a new version called if-modified.txt where all occurrences of the first word are replaced by the second.

5. Ask the user to enter four lines of their own poem. Write each line to a new file called poem.txt. Verify it wrote correctly by opening the file.

If you have time, try the next steps:

1. Read the if.txt file, and write another file if-reversed.txt where the lines are in reverse order (the last line of the input file becomes the first line of the output file).

2. Read the if.txt file and count how many times each alphabetic character appears (a-z), ignoring capitalization. Use a dictionary to store the frequency of each character, and print the result.

3. Download and save the file video_games.tsv to your cs100/ch5 folder. Be sure to use the same name for the file. This is a tab-delimited data file (each field is separated by a tab character). This can be opened with Excel, Numbers, or some other spreadsheet application. You may browse the file and see the type of data that is present. Copy the following code into your python file, saved to the same cs100/ch5 folder. It has a sample function which shows how to get data and calculate the average used price of a game published by Nintendo.

# DATA INDEX VALUES
# Use to access certain data fields in the list
GAME_TITLE = 0
PUBLISHER = 1
REVIEW_SCORE = 2
USED_PRICE = 3
CONSOLE_NAME = 4
ESRB_RATING = 5
RELEASE_YEAR = 6


# return game data as a list of records
# where each record is a list of string fields
def get_data():
    data_records = []
    with open('video_games.tsv', 'r') as game_data:
    
        # dispose of TSV header
        game_data.readline()
            
        # collect all records
        for line in game_data:
            allFields = line.split('\t')   # separated by tabs
            allFields[-1] = allFields[-1].replace("\n","") # get rid of newline
            data_records.append(allFields) # each record contains list of all fields
        
    return data_records


# return the average price of a Nintendo game
def avg_nintendo_game_price():
    count = 0          # count of games
    running_total = 0  # running total of prices used to calculate average

    # Go through each record from the file.
    # Each record is a list of fields.
    for record in get_data():

        # Use the PUBLISHER index to get the name of the publisher
        if record[PUBLISHER] == 'Nintendo':
            # Use the USED_PRICE index to get the used cost of the game
            running_total += float(record[USED_PRICE])
            count += 1
    
    # Use the count and the sum of all prices to compute an average
    # Then, round to nearest 2 decimal places
    avg = running_total / count
    return round(avg, 2)

# TODO: Define your functions here (all function definitions MUST
#    return data and NOT use the print function)


# TODO: Call the functions you defined here and print the data they return neatly
# For example, this prints the result of the function call to find the average nintendo price
print("Average price of Nintendo Games: ${0}".format(avg_nintendo_game_price()) )

Take some time to explore the data. Come up with three additional functions that present some information about the dataset. Some ideas might be:

• How many game titles were released by a certain publisher? (e.g., num_titles_released_by(publisher))
• How many games are rated over a certain score? (num_games_over(score))
• What game has the highest used price value?
• How many games were released in a specific year?
• What year has the most games released?
• What is the averge score of all games made by a certain publisher?
• What games has the longest title?

None of your function definitions should print. They should all use the return statement to provide data. When you call your function, you will print the output to the screen neatly with a clear explanation of what the value represents (this will use the print function). Use the existing code as a guide.

How to submit

Make sure you saved your work and that it runs without errors. Submit your your python file to Moodle.