Python Speed Optimization: Retrieve Values from a Dictionary Over 50% Faster!

Discover a trick that can significantly speed up value retrieval from Python dictionaries.

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In daily work, most of the time it is required to extract multiple values from a Python dictionary in correspondence to multiple keys. This can be achieved by writing a for loop like this:

items = list()
for key in keys:
  items.append(dict_[keys])

Or can be written as a one-line loop like this:

[dict_[key] for key in keys]

However, this can, sometimes, lead to growing runtime complexity as the loops grows with the number of keys to be extracted.

A better solution would be to use python ‘operator’.

list(operator.itemgetter(*keys)(dict_to_get_from))

This is not only cleaner, but also ~50% faster after experimenting it!

In the following experience, I tried both methods on a mock dictionary and, on average, the ‘itemgetter’ is ~1.9 times faster than list comprehension.