Tag: Python

Here’s a lesson on “falseness”- that is, whether values are classified as True or False in Python.

I’m working on a Codecademy project (Abruptly Goblins) where there’s a gamer named Kimberly who is available to play on Monday, Tuesday and Friday. There will be other gamers added in later.

Let’s make a dictionary with name and availability as keys.
We’ll also make an empty list called gamers to store valid gamer details.

gamers = []
kimberly = {"name":"Kimberly Chook", "availability": ["Monday", "Tuesday", "Friday"]}

The project instructions say to:
Create a function called add_gamer that takes two parameters: gamer and gamers_list. The function should check that the argument passed to the gamer parameter has both "name" and a "availability" as keys and if so add gamer to gamers_list.

The number of times ‘gamer’ and variants are being tossed around make these instructions confusing as heck! But I plow through. Here’s what I came up with:

def add_gamer(gamer, gamers_list): #gamers_list is the parameter. gamers = [] is what the parameter value will be (argument).
    if gamer.get("name") and gamer.get("availability"): # Access name and avail values if they exist. If any keys not found, returns None.
        gamers_list.append(gamer)
    else: print("Failure, Gamer doesn't have name or availability")

Notice the if statement here. It seems incomplete to me:
if gamer.get(“name”) and gamer.get(“availability”):

We will be inserting gamer dictionary arguments. If it doesn’t contain “name” or “availability” as a key, the .get() method will return None (because it did not find the key, and thus has no corresponding value).

But there is something weird assumed here. If the gamer argument does contain keys of “name” and “availability”, the if statement is True, so proceed with the function (appending the player’s details to the gamer list).

1. Why do the two .get() statements result in a True / pass go, collect $200?

2. If any of the .get() statements results in a None, why is that a False / do not pass go, do not collect $200?

The answer to #1 is still unknown to me, but I did find out #2 from Stack Overflow:

The expression x or y evaluates to x if x is true, or y if x is false.

Note that “true” and “false” in the above sentence are talking about “truthiness”, not the fixed values True and False. Something that is “true” makes an if statement succeed; something that’s “false” makes it fail. “false” values include False, None, 0 and [] (an empty list).

from Stack Overflow https://stackoverflow.com/questions/3914667/false-or-none-vs-none-or-false

When any .get() statements results in a None, that is of the “False” category in Python so it will not proceed. I tested this out by running:

gamers = []

def add_gamer(gamer, gamers_list):
    if gamer.get("name") and gamer.get("availability"):
        gamers_list.append(gamer)
    else: print("Failure, Gamer doesn't have name or availability")

kimberly = {"notname":"Kimberly Chook", "availability": ["Monday", "Tuesday", "Friday"]}
print(kimberly.get("name" and gamer.get("avialability")))

>>> None

So when you ask your partner “Did you clean the bathroom yet?” and get no response for an answer (none, nada, nothing), you can interpret that as: status_bathroom_is_clean = False.