给定一个以字符串列表作为其值的字典，您将如何检索列表包含所有其他列表唯一的字符串的所有键？

Question

As an example if the dictionary was this:

myDict = {"egg sandwich":["bread", "lettuce", "mayo","egg"], 
          "sad sandwich":["bread","lettuce","mayo"],
          "ham sandwich":["bread","lettuce","mayo","ham"],
          "healthy sandwich":["lettuce"],
          "breakfast sandwich":["bread","egg","mayo"]}

The function should return "ham sandwich" , since it is the only sandwich that contains an ingredient (ham) unique to a comparison of all other lists.

Answer 1

This seems to work:

def get_unique_item(d):
    all_ingredients = [y for x in d.values() for y in x]

    output = []
    for name, ingredients in d.items():
        for ingredient in ingredients:
            if all_ingredients.count(ingredient) == 1:
                output.append(name)
                break

    return output

myDict = {"egg sandwich":["bread", "lettuce", "mayo","egg"], 
          "sad sandwich":["bread","lettuce","mayo"],
          "ham sandwich":["bread","lettuce","mayo","ham"],
          "healthy sandwich":["lettuce"],
          "breakfast sandwich":["bread","egg","mayo"]}


print(get_unique_item(myDict))

Output:

['ham sandwich']

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Basically, we create a list of all occurrences of all ingredients, and for each sandwich, we check if there are any ingredients which only occur once.

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If you really want to, you can make it a one-line list comprehension:

[name for name, ingredients in d.items() if any([y for x in d.values() for y in set(x)].count(i) == 1 for i in ingredients)]