CODEWITHSUNDEEP
pythondictionarylambda
David
David

Reputation: 1267

Using map and lambda to emulate a dict comprehension

I have a list of tuples that are coordinates: xy = [(x_1, y_1), (x_2, y_2), ...] and an specific point xy_sp = [x_sp, y_sp]. I want to calculate the distance from each point to the so called "specific point" and to create a dictionary in the form: {coordinates_of_1st_point: distance_1, coordinates_of_2nd_point: distance_2, ...} and then perhaps I just can order my dictionary by values.

I want to do this with a functional pythonic approach. So I did:

import numpy as np
distances = list(map(lambda k: np.linalg.norm(np.asarray(k) - np.asarray(xy)), xy))

And then I just created a dictionary comprehension:

dict_distances = {k : v for k, v in zip(xy, distances)}

It is this last point that I want to do with a maps and lambdas in a functional approach but I don't know how to do it. If it can be all done in a line of code it would be interesting, although I suppose it will be not readable at all and therefore not very recommendable.

Any suggestions are welcomed.

Upvotes: 1

Views: 355

Answers (1)

Moses Koledoye
Moses Koledoye

Reputation: 78554

You don't need a lambda for that, just call the built-in dict on the result from zip:

dict_distances = dict(zip(xy, distances))

Builds a mapping from the 2-tuple returned by zip.

Upvotes: 3

Related Questions