How to Efficiently Retrieve List of Values from Multiple Keys in a Dictionary?

Retrieve List of Values from Multiple Keys using Dict Comprehension

Accessing specific values from a dictionary using individual keys is a straightforward operation. However, when working with multiple keys, a more efficient approach is required.

Consider a scenario where you have a dictionary mydict containing key-value pairs and a list mykeys of specific keys you want to extract values for. The ultimate goal is to obtain a new list that contains the corresponding values from mydict in the same order as the mykeys list.

Solution: Dict Comprehension

Python offers a powerful tool called list comprehension, which allows for concise and elegant code construction. To achieve the desired result, a list comprehension can be employed as follows:

<code class="python">[mydict[x] for x in mykeys]</code>

In this comprehension:

• The outer square brackets create a new list as the final output.
• The loop variable x iterates over each element in the mykeys list.
• Inside the loop, mydict[x] retrieves the value associated with the current key x.
• The result is a list containing the values corresponding to the keys in mykeys.

For your specific example:

<code class="python">mydict = {'one': 1, 'two': 2, 'three': 3}
mykeys = ['three', 'one']

result = [mydict[x] for x in mykeys]

print(result)  # Output: [3, 1]</code>

This solution efficiently generates a new list result that contains the values for the specified keys in mykeys. It maintains the order of the keys, allowing you to easily align the output values with their corresponding keys.

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