Get key and indices of selected elements Swift

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失恋的感觉
失恋的感觉 2021-01-27 23:41

I have one dictionary that contains an Array of Dictionaries.

\"other\":(
    {
         \"grocery_section\" = other,
         name = test
    },
    {
                  


        
2条回答
  •  暖寄归人
    2021-01-27 23:50

    You can make use of flatMap and compactMap:

    let matches = list.flatMap { key, value in
        // go through all elements in the array and convert the matching dictionaries in (key, index) pairs
        value.enumerated().compactMap { index, dict in
            dict["name"] == "test" ? (key, index) : nil
        }
    }
    print(matches)
    

    Sample output:

    [("other", 0), ("c0f5d6c5-4366-d310c0c9942c", 1)]
    

    If you want to avoid repeated pairs for the same key, you can use map instead of compactMap:

    let matches = list.map { key, value in
        (key, value.enumerated().compactMap { index, dict in
            dict["name"] == "test" ? index : nil
        })
    }
    

    Sample output:

    [("other", [0]), ("c0f5d6c5-4366-d310c0c9942c", [1])]
    

    The inner compactMap will build an array made of on only the items that have the name matching, while the outer flatMap will flatten an otherwise bi-dimensional array.

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