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I need to make a dictionnary containing only keys.
I cannot use d.append() as it is not a list, neither setdefault as it needs 2 arguments: a key and a value.
It should work as the following:
d = {}
add "a":
d = {"a"}
add "b":
d = {"a", "b")
add "c" ...
#Final result is
d = {"a", "b", "c"}
What is the code I need to get this result? Or is it another solution? Such as making a list.
l = ["a", "b", "c"] # and transform it into a dictionnary: d = {"a", "b", "c"} ?
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Dictionaries in Python Almost any type of value can be used as a dictionary key in Python. You can even use built-in objects like types and functions. However, there are a couple restrictions that dictionary keys must abide by. First, a given key can appear in a dictionary only once.
Keys are unique within a dictionary while values may not be. The values of a dictionary can be of any type, but the keys must be of an immutable data type such as strings, numbers, or tuples.
To create an empty dictionary, first create a variable name which will be the name of the dictionary. Then, assign the variable to an empty set of curly braces, {} . Another way of creating an empty dictionary is to use the dict() function without passing any arguments.
A dict with only keys is called a set.
Start with an empty set instead of a dictionary.
d = set()
d.add('a')
d.add('b')
d.add('c')
You can also create a set via a {} expression:
d = { 'a', 'b', 'c' }
Or using a list:
d = set(['a', 'b', 'c'])
That should do it:
l = ["a", "b", "c"]
d = {k:None for k in l}
As @Rahul says in the comments, d = {"a", "b", "c"} is not a valid dictionary definition since it is lacking the values. You need to have values assigned to keys for a dictionary to exist and if you are lacking the values you can just assign None and update it later.
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