如何仅从字典中提取键

Question

I'm trying to create a dict to not use lots of if statements, but for some reason, I cannot seem to make it work the way I want. I'm trying to pull out only the keys from the dict when the correspond to the inputted day.

Thanks in advance.

edit: expected input/output

Input (Day of Week)	Output (Corresponding key)
'Monday'	12
'Tuesday'	12
'Friday'	12
'Wednesday'	14
'Thursday'	14
'Saturday'	16
'Sunday'	16

day = str(input())

day_price_dict = {12: ['Monday', 'Tuesday', 'Friday'], 14: ['Wednesday', 'Thursday'], 16: ['Saturday', 'Sunday']}

if day in day_price_dict:
    print(day_price_dict[day])

Answer 1

Following should do what you want:

# example: day = 'Tuesday'
day = str(input())

day_price_dict = {12: ['Monday', 'Tuesday', 'Friday'], 14: ['Wednesday', 'Thursday'], 16: ['Saturday', 'Sunday']}

# iterate through dict keys (12, 14, 16)
for key in day_price_dict:
    # if input is in the value list, print the key
    if day in day_price_dict[key]:
        # print 12
        print(key)

Answer 2

Your conceptualization seems off: What you want is probably a mapping from days to prices rather than vice versa, ie,

>>> day_prices = {'Monday': 12,
                  'Tuesday': 12,
                  'Wednesday': 14,
                  'Thursday': 14,
                  'Friday': 12,
                  'Saturday': 16,
                  'Sunday': 16}

>>> day_prices["Monday"]
12

Answer 3

you can get the keys like this:

keys = day_price_dict.keys()
# if you want a list:
keys = list(day_price_dict.keys())

You can also get the value:

for value in day_price_dict.value():
   print(value)

Or both

for key, value in day_price_dict.items():
    print(f"key: {key} -- value: {value}")

Answer 4

In Python 3 list() function takes any iterable as a parameter and returns a list. In Python iterable is the object you can iterate over. You can simply use the below lines to get the list of keys.

day_price_dict = {12: ['Monday', 'Tuesday', 'Friday'], 14: ['Wednesday', 'Thursday'], 16: ['Saturday', 'Sunday']}
keys_list = list(day_price_dict.keys())
print(keys_list)