如何从python中具有相同键和值的字符串列表创建字典

Question

I have a list of strings with no duplicate elements and I need to generate a dictionary with elements of this list as key and values of this dictionary.

List: file_names = ['a', 'bb', 'ccc', 'ad', 'rsb']

Desired dictionary:

file_names = {'a': 'a', 'bb':'bb', 'ccc': 'ccc', 'ad': 'ad', 'rsb':'rsb'}

I want each element of list be as the key and also exactly have that element as it's value for that key. What is the best (most fast) way for generating such a dictionary in python specifically python 2?

Answer 1

Please consider using a set instead if all you wish to do is check if an element is in a collection. This gives you O(1) complexity for membership tests. You can convert a list to a set by doing

file_names = set(['a', 'bb', 'ccc', 'ad', 'rsb'])
file_names = set(file_names)

Then, you can check for membership by simply doing

if file_name in file_names: