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How to check if a dictionary is a proper subset of another dictionary in Python

How to check if a dictionary is a proper subset of another dictionary in Python.

Here's a detailed step-by-step tutorial on how to check if a dictionary is a proper subset of another dictionary in Python.

First, let's understand what a proper subset means. A proper subset is a subset that contains all the elements of another set, but with at least one additional element.

To check if a dictionary is a proper subset of another dictionary, we'll follow these steps:

Step 1: Define the two dictionaries​

  • Start by defining the two dictionaries that you want to compare. Let's call them dict1 and dict2.

Step 2: Check if dict1 is a subset of dict2​

  • Use the items() method on dict1 to get a list of key-value pairs.
  • Iterate through each key-value pair using a loop.
  • For each key-value pair, check if the key exists in dict2 and if the corresponding value matches.
  • If any key-value pair in dict1 doesn't match the corresponding pair in dict2, dict1 is not a subset of dict2.

Here's an example code snippet to perform this step:

for key, value in dict1.items():
    if key not in dict2 or dict2[key] != value:
        print("dict1 is not a proper subset of dict2")
        break

Step 3: Check if dict1 is a proper subset (additional step)​

  • After checking if dict1 is a subset of dict2 in the previous step, we need to confirm if dict1 has at least one additional key-value pair.
  • To do this, compare the lengths of dict1 and dict2. If the length of dict1 is equal to the length of dict2, then dict1 is not a proper subset.

Here's an example code snippet to perform this step:

if len(dict1) == len(dict2):
    print("dict1 is not a proper subset of dict2")
else:
    print("dict1 is a proper subset of dict2")

Here's a complete example that puts all the steps together:

dict1 = {'a': 1, 'b': 2}
dict2 = {'a': 1, 'b': 2, 'c': 3}

for key, value in dict1.items():
    if key not in dict2 or dict2[key] != value:
        print("dict1 is not a proper subset of dict2")
        break
else:
    if len(dict1) == len(dict2):
        print("dict1 is not a proper subset of dict2")
    else:
        print("dict1 is a proper subset of dict2")

In this example, dict1 is a proper subset of dict2 because it contains all the elements of dict2 and has an additional key-value pair ('c': 3).

I hope this tutorial helps you check if a dictionary is a proper subset of another dictionary in Python!