Reverse Lookup Dict Of Tuples, Or Use A Different Data Structure?

I currently have a dictionary of tuples like this: d = { 0: ('f', 'farm'), 1: ('m', 'mountain'), 2: ('h', 'house'), 3: ('t', 'forest'), 4: ('d', 'desert') } It

Solution 1:

There are already similar questions that you could use as a starting point.

How to implement an efficient bidirectional hash table?Reverse / invert a dictionary mapping

In your specific case, the dict in its current form may be pointless. Dicts with integer keys starting from zero are just inefficient lists, but lists already have a reverse lookup method called index.

So what you could do is:

places_order = ['f', 'm', 'h', 't', 'd']

and then use places_order.index(some_letter) to get the corresponding integer. This is an O(n) operation, so I'm assuming you don't need to perform these lookups millions of times with high performance. (Otherwise, especially if the real places_order is a long list, consider dict(zip(places_order, range(len(places_order)))).)

In addition, you could keep a map for the abbreviations of place names.

abbreviations = {
    'f': 'farm',
    'm': 'mountain',
    'h': 'house',
    't': 'forest',
    'd': 'desert'
}

It's hard to say more without knowing any specifics about what you are trying to achieve.

Solution 2:

A most straightforward search would be:

defsearch(dictionary, word):
    for key,value in dictionary.items():
        if word in value:
            return key

This could then be used as:

>>> search(d, 'h')
2

Solution 3:

Not sure I fully understand the use-case, but if you are not looking for a built-in python what about pandas.Series:

import pandas as pdd= pd.Series(['farm', 'mountain', 'house', 'forest', 'desert'],index = ['f', 'm', 'h', 't', 'd'])

so both d[0] and d['f'] will output 'farm', d.index[0] will give 'f' and d.index.get_loc('f') will give 0.

For the case of built-ins see @timgeb's answer or consider a sort of namedtuple.

Solution 4:

Here is another approach:

d = {
    0: ('f', 'farm'),
    1: ('m', 'mountain'),
    2: ('h', 'house'),
    3: ('t', 'forest'),
    4: ('d', 'desert')
}
for key, value in d.items():
    if'h'in value:
        print (key)
        break

Solution 5:

You can use a dict like this:

abs = {
'f': 'farm',
'm': 'mountain',
'h': 'house',
't': 'forest',
'd': 'desert'
}

when you need to reverse loop:

for i, (key, value) inenumerate(abs.items()):
    print(i, key, value)  # 0 f farm

when you want items by index:

list(abs.items())[i]  # ('f', 'farm')