I have an asymmetrical nested list. Each element of the deepest list represents a person. So in this example there are three people.

data = {{4, 7, 0}, {10, 5, 10}, {{1, 4, 4}, {9, 3, 5}, {{1, 4, 9}, {10, 5, 4}}}}

Each element of the outer list has different depths. The form is: data = {data1, data2, {data3, data4, {data5, data6}}}

I want to extract the first element (or the first person) of the deepest list for each element, while keeping the same nested list format.

The desired output is {4,10,{1,9,{1,10}}}

I do not know the depth of each nested list, but want code that would look for the deepest list within each element and extract that first element.


1 Answer 1


Here is one possibility:

Replace[data, {a_,__} :> a, {-2}]

{4, 10, {1, 9, {1, 10}}}


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