Nov 22: Prac6, Help with Project

Learning Objectives

After today's class, you should be able to:

• Write a list comprehension that includes an expression and a condition.
• Explore the contents of a relatively complex object stored in a JSON file.
• Read and write data in JSON files using json.load() and json.dump().

Practice Quiz

• List comprehensions

  • See zyBook and Real Python

  • Example 1: Squaring Numbers

    # Before
    squares = []
    for x in range(10):
        squares.append(x**2)
    
    # After
    squares = [x**2 for x in range(10)]
    

  • Example 2: All Caps Words

    text = "JMU is the BEST"
    
    # Before
    caps = []
    for word in text.split():
        if word.isupper():
            caps.append(word)
    
    # After
    caps = [word for word in text.split() if word.isupper()]
    

• Exploring skyscrapers.json

  • Loading the data from the JSON file
    Note: This was done before calling your function.

    import json
    from pprint import pprint
    
    with open("skyscrapers.json") as file:
        data = json.load(file)
    

  • Lists use indexes. Dictionaries use keys.

    >>> data[0]["name"]
    'The Illinois'
    
    >>> data[0]["statistics"]["height"]
    1609.3599853516
    

Hints on PA3

• Part B: Nested Data

  • Command-line arguments
    • sys.argv
    • sys.exit()
  • F-string field width

    x = 149
    y = 159
    print(f"|{x:10d}|{y:10d}|")
    s = "Hi!"
    t = "Ho!"
    print(f"|{s:10s}|{t:10s}|")
    

• Part C: Recursion

  • Influence of a user depends on their friends' influence
  • Need to recursively call the function on each friend

• Part D: API Usage

  • Walk through the provided fulltracks.py module
  • How to call another API method (based on the docs)