When working with dictionaries in Python, you might come across a situation where you need to change all the values in a dictionary. In this tutorial, we will learn how to change all values in a dictionary using Python.
Changing the values in a dictionary can be useful in various scenarios, such as updating data values or applying transformations to the data. We will use simple dictionary comprehension techniques and some built-in Python functions to achieve this task.
Step 1: Create a Dictionary
First, let’s create a sample dictionary to work with. The keys can be anything, but for this tutorial, we will use strings as keys and integers as values.
my_dict = {“apple”: 1, “banana”: 2, “cherry”: 3}
print(my_dict)
Output:
{'apple': 1, 'banana': 2, 'cherry': 3}
Step 2: Change All Values Using Dictionary Comprehension
Now, let’s change all values in the dictionary by adding 5 to each. We can use dictionary comprehension in a single line to achieve this:
new_dict = {key: value + 5 for key, value in my_dict.items()}
print(new_dict)
Output:
{'apple': 6, 'banana': 7, 'cherry': 8}
This code uses a for loop to iterate over all key-value pairs in the dictionary, adds 5 to each value, and creates a new dictionary with the updated values.
Step 3: Implement a Custom Function to Change Values
If you need to apply a more complex transformation to the values or want to leave the original dictionary unchanged, you can create a function to do so:
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def update_values(dict_input, update_function): return {key: update_function(value) for key, value in dict_input.items()} def add_five(x): return x + 5 my_dict = {"apple": 1, "banana": 2, "cherry": 3} new_dict = update_values(my_dict, add_five) print(new_dict) |
Output:
{'apple': 6, 'banana': 7, 'cherry': 8}
In this example, we created a function called update_values that takes a dictionary and a function as inputs, applies the function to each value in the dictionary, and returns a new dictionary with the updated values. The add_five function simply adds 5 to a given number.
Full Code
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def update_values(dict_input, update_function): return {key: update_function(value) for key, value in dict_input.items()} def add_five(x): return x + 5 my_dict = {"apple": 1, "banana": 2, "cherry": 3} new_dict = update_values(my_dict, add_five) print(new_dict) |
Output:
{'apple': 6, 'banana': 7, 'cherry': 8}
Conclusion
In this tutorial, we learned how to change all values in a dictionary using Python.
We saw how to use dictionary comprehension to make quick changes to our dictionary, and we also learned how to create a custom function to apply more complex transformations to our dictionary values.
This method can be easily adapted to any other transformation or update you need to make to your dictionary values.