which is better- storing data as array or json?

for indexing, accessing, filtering and searching?

as simple array-
first name | last name | nicknames
tom | jerry | {cat}, {mouse}

as multi-dimensional array-
first name | last name | nicknames
tom | jerry | {cat, kat}, {mouse, mice}

as simple json-
first name | last name | nicknames
tom | jerry | {"public": "cat", "private": "mouse"}

as multi-nested json-
first name | last name | nicknames
tom | jerry | {"public": {"first": "cat", "second": "kat"},
"private": {"first": "mouse", "second": "mice"}}