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Erlang / Erlang Basics Interview questions

What is the difference between a list and a tuple?

Both are ordered Erlang data structures, but they're built and used very differently.

ListTuple
Variable length; a linked chain of head/tail cons cells. Fixed length, decided at creation; contiguous positions.
Cheap to prepend to ([X|List]); processed recursively. Cheap to access any known position directly, e.g. element(2, T).
Good for sequences of unknown/variable size. Good for fixed-shape records like {ok, Value}.

A rule of thumb: if you don't know how many elements you'll have, or the count will vary, use a list. If the shape and number of fields is fixed and known up front, a tuple (often tagged with a leading atom) is the better fit.

Which structure would you choose for an unknown, possibly-growing sequence of items?
What is a common way to access one specific field out of a tuple?

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