How do I extract the components of a tuple in DAML?

Question

Given a pair in DAML, e.g. constructed by (1, "test"), how can I get the first and second components out?

Can you show us your code? What have you tried? What were you expecting the result to be? — Bob Dalgleish, Dec 13 '18 at 14:04

score 2 · Accepted Answer · answered Dec 13 '18 at 14:38

Given a DAML pair x of type (Int, Text), you can get the first component (1 in your example) using the selector x._1 or the fst function as fst x. You can get the second component ("test" in your example) with x._2 or snd x.

The x._1 selector works on all tuples (pairs, triples and beyond), while fst only works on pairs. The function fst3 (and snd3, thd3) are available in DA.Tuple to work on triples.

score 1 · Answer 2 · answered Aug 07 '19 at 07:08

1

For a tuple that has a number of elements, you could use

let (a,_,c,_) = someFunction

-- do something to a or c

answered Aug 07 '19 at 07:08

Frankie

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How do I extract the components of a tuple in DAML?

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