Python Fastest way to find Indexes of item in list

Question

If one was to attempt to find the indexes of an item in a list you could do it a couple different ways here is what I know to be the fastest

aList = [123, \'         


        

Answer 1

To get the index of the item, you can use the dictionary.

aList = [123, 'xyz', 'zara','xyz', 'abc'];
#The following apporach works only on lists with unique values
aList = list(np.unique(aList)); 
dict = enumerate(aList);
# get inverse mapping of above dictionary, replace key with values
inv_dict = dict(zip(dict.values(),dict.keys()))
# to get index of item by value, use 'inv_dict' and to get value by index, use 'dict'
valueofItemAtIndex0 = dict[0]; # value = 123
indexofItemWithValue123 = inv_dict[123]; # index = 0