Skip to main content

2D Dictionaries

   


2D Dictionaries 

Remember that dictionaries are very similar to lists, except that they store data as key:value pairs. The value is what it's worth and the key is what it is called. The key is used to access the value, and keys are more meaningful than index numbers.


Today we are going to expand our mad dictionary skills into the second dimension. 


Dynamically Adding To A 2D Dictionary 

This code dynamically adds to a 2D dictionary by starting with an empty dictionary and using an infinite loop to add user input.

EXAPMLE:

clue = {}
while True:
  name = input("Name: ")
  location = input("Location: ")
  weapon = input("Weapon: ")
  clue[name] = {"location": location, "weapon":weapon}#line 7
  print(clue)

The real magic happens on the 7th line of code. Instead of using .append() like we would with a list, we create a new dictionary entry.

The key is the name of the beast, but the value is a whole new dictionary that contains the details of the beast.
Each key:value pair in the dictionary is now a key that accesses a related dictionary.




Pretty Printing

This example shows you how to add a prettyPrint() subroutine that works with a 2D dictionary. 
 
def prettyPrint():
  print()
  
  for key, value in clue.items():
    # moves along every 'key:subDictionary' pair and outputs the key (the name of the character).
    print(key, end=": ")
    for subKey, subValue in value.items():
      # (nested) `for` loop moves along every subkey and subvalue in each subDictionary.
      print(subKey, subValue, end=" | ")
    print() 

Accessing a Single Item 

To access a single item in a 2D dictionary, we use two square brackets just like with a 2D list. 


his example stores users' data about their 100 Days Of Code progress. Note how I've set each one up as a 1D dictionary before storing them all in a 2D dictionary. 


john = {"daysCompleted": 46, "streak": 22}
janet = {"daysCompleted": 21, "streak": 21}
erica = {"daysCompleted": 75, "streak": 6}
courseProgress = {"John":john, "Janet":janet, "Erica":erica}
print(courseProgress) 

To access one item, I use two square brackets []. So to see only Erica's results, I would add:


print(courseProgress["Erica"])
# The bracket contains the key that references the sub dictionary.

👉 What if we only want to see how many days Erica has completed?


john = {"daysCompleted": 46, "streak": 22}
janet = {"daysCompleted": 21, "streak": 21}
erica = {"daysCompleted": 75, "streak": 6}
courseProgress = {"John":john, "Janet":janet, "Erica":erica}
print(courseProgress["Erica"]["daysCompleted"])
# The first bracket contains the key that references the sub dictionary. The second bracket contains the key that references the sub item. This will output '75'.


Comments

Post a Comment

Popular posts from this blog

Hide & Remove,Come Back!,

 Hide & Remove DISCLAIMER: I promise the good stuff is coming back. We have to go through the valley to get to the mountain, right? Sometimes, we want to remove a button, image or piece of text from the screen. To do this, we use pack_forget(). 👉 We'll start with our default tkinter program. import tkinter as tk window = tk.Tk() window.title("Hello World")  window.geometry("300x200")  hello = tk.Label(text = "Hello World")  hello.pack()  button = tk.Button(text = "Click me!")  button.pack() tk.mainloop() 👉 Now I'm going to add a new subroutine to hide the label and call it on a button click. import tkinter as tk window = tk.Tk() window.title("Hello World")  window.geometry("300x200")  # New subroutine def hideLabel():   hello.pack_forget() # Removes the 'hello' label hello = tk.Label(text = "Hello World")  hello.pack()  button = tk.Button(text = "Click me!", command = hideLabel) # Call...
Post a Comment
Read more

String Manipulation

   String Manipulation Does this code look familiar from the insult generator project? name = input("What's your name? ") if name == "David" or name == "david":   print("Hello Baldy!") else:    print("What a beautiful head of hair!") Right now, if the user writes "DAVID" or "david", the if statement works correctly. However, "DaVID" does not give the correct output. To the computer, " david", "dAviD", and "david" are completely different. To simplify what the user typed in, we can add these functions to the end of the name of the variable: .lower() = all letters are lower case .upper() = all letters are upper case .title() = capital letter for the first letter of every word .capitalize() = capital letter for the first letter of only the first word    
Post a Comment
Read more

Web Scraping

 Web Scraping Some websites don't have lovely APIs for us to interface with. If we want data from these pages, we have to use a tecnique called scraping. This means downloading the whole webpage and poking at it until we can find the information we want. You're going to use scraping to get the top ten restaurants near you. Get started 👉 Go to a website like Yelp and search for the top 10 reastaurants in your location. Copy the URL.   url = "https://www.yelp.co.uk/search?find_desc=Restaurants&find_loc=San+Francisco%2C+CA%2C+United+States"   Import libraries 👉 Import your libraries. Beautiful soup is a specialist library for extracting the contents of HTML and helping us parse them. Run the Repl once your imports are sorted because we want the Beautiful Soup library to be installed (it'll run quicker this way). import requests from bs4 import BeautifulSoup url = "https://www.yelp.co.uk/search?find_desc=Restaurants&find_loc=San+Francisco%2C+CA%2C+Unite...
Post a Comment
Read more