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max() for a dictionary

Posted on January 12, 2021

I’m not a programmer, but does a dictionary in which all its elements have the same key make a lot of sense?



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Hello,

Frankly speaking, that is not recommended for the security reasons. In python, if we want a dictionary in which one key has multiple values, then we need to associate an object with each key as value. This value object should be capable of having various values inside it. We can either use a tuple or a list as a value in the dictionary to associate multiple values with a key.

Can you elaborate a bit more on your use case?

Hope this helps!

Cheers, Sri Charan

Heya all,

In Python, a dictionary where all elements have the same key doesn’t actually work as you might expect because each key in a dictionary must be unique. If you try to create a dictionary with multiple elements having the same key, what happens is that each new assignment to that key overwrites the previous value. Here’s what I mean:

my_dict = {}
my_dict['key'] = 'value1'
my_dict['key'] = 'value2'
my_dict['key'] = 'value3'

print(my_dict)  # Output will be {'key': 'value3'}

In this example, the dictionary only retains the last assignment (‘value3’) for the key ‘key’. All previous values assigned to this key are overwritten.

Practical Usage of Dictionaries

Dictionaries are typically used to store data in key-value pairs where each key is unique. This makes dictionaries incredibly useful for cases where you need to efficiently look up, insert, or modify data associated with a unique identifier. Here are a few examples:

  1. Storing User Information: Each user’s unique ID could be a key, and their information (name, email, etc.) could be the value.
  2. Configurations: Keys could be configuration setting names, and values could be the settings themselves.
  3. Counting: Dictionaries are great for counting occurrences of items, where the keys are the items to count, and the values are the counts.

Using max() on a Dictionary

If you’re looking to use max() on a dictionary, it depends on what you’re trying to find the maximum of:

  • Maximum Key: By default, max() when applied to a dictionary will return the maximum key according to standard comparison rules.
  • Maximum Value: If you’re interested in finding the key associated with the maximum value, you can use max() with a key function:
my_dict = {'a': 1, 'b': 5, 'c': 3}
max_key = max(my_dict, key=lambda k: my_dict[k])
print(max_key)  # Outputs 'b'

This code snippet finds the key with the maximum value, which in this case is ‘b’ because it has the highest value (5).

In summary, a dictionary with all elements having the same key isn’t practical or possible in Python because only the last value set for that key is retained. If you have multiple values that need to be stored under a ‘similar’ key, you might consider using a list of tuples, or a dictionary where each key is linked to a list of values.

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