Tuples and records ​

Pairs ​

(a1, a2) denotes a pair in SmartPy. If a1 is of type t1 and a2 is of type t2, then (a1, a2) is of type sp.pair[t1, t2]. For example, (42, "abc") is of type sp.pair[sp.int, sp.string].

sp.fst(sp.pair[t1, t2]) → t1

Extracts the first component of a pair. For example, sp.fst((42, "abc")) == 42.

sp.snd(sp.pair[t1, t2]) → t2

Extracts the second component of a pair. For example, sp.snd((42, "abc")) == "abc".

Tuples ​

More generally, SmartPy supports tuples with arbitrary many components. For example, (42, "abc", True) is of type sp.tuple[sp.int, sp.string, sp.bool].

Tuples can be matched on the left-hand side of assignments, for example:

(a, b, c) = (42, "abc", True)
assert a == 42
assert b == "abc"
assert c == True