Python - Assigning Key values to list elements from Value list Dictionary

Python - Assigning Key values to list elements from Value list Dictionary

In this tutorial, we'll explore how to assign key values to list elements using a dictionary that maps those list elements to their corresponding values.

Problem:

Given a list of elements and a dictionary where keys are list elements and values are their corresponding values, map each element in the list to its value from the dictionary.

For instance, consider the list:

elements = ['apple', 'banana', 'orange']

And the dictionary:

value_dict = {'apple': 10, 'banana': 20, 'orange': 30}

We want to transform the elements list to:

[10, 20, 30]

Solution:

Using List Comprehension:

List comprehension offers a concise way to achieve the desired transformation.

Here's how you can do it:

def map_elements_to_values(elements, value_dict):
    return [value_dict[element] for element in elements if element in value_dict]

elements = ['apple', 'banana', 'orange']
value_dict = {'apple': 10, 'banana': 20, 'orange': 30}
mapped_values = map_elements_to_values(elements, value_dict)
print(mapped_values)  # Output: [10, 20, 30]

Notes:

  • The if element in value_dict condition ensures that we only try to access keys that are present in the dictionary. If elements contains any element not present as a key in value_dict, this condition prevents a KeyError.
  • If you know that all elements in the list are guaranteed to be keys in the dictionary, you can omit this condition.

This tutorial provided a method to map list elements to their corresponding values in a dictionary. This is a common operation in data transformation and preprocessing when you have a mapping defined and want to convert a list of keys into a list of their associated values.

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