How to set std::tuple element by index?

Question

One can get an element from std::tuple by index using std::get. Analogically, how to set tuple's element by index?

Nicol Bolas · Accepted Answer · 2013-02-10 00:04:47Z

186

std::get returns a reference to the value. So you set the value like this:

std::get<0>(myTuple) = newValue;

This of course assumes that myTuple is non-const. You can even move items out of a tuple via std::move, by invoking it on the tuple:

auto movedTo = std::get<0>(std::move(myTuple));

answered Sep 17, 2011 at 8:50

Nicol Bolas

481k66 gold badges861 silver badges1.1k bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Nicol Bolas · Accepted Answer · 2012-09-20 14:31:45Z

29

The non-const version of get returns a reference. You can assign to the reference. For example, suppose t is tuple, then: get<0>(t) = 3;

Nicol Bolas

481k66 gold badges861 silver badges1.1k bronze badges

answered Sep 17, 2011 at 8:51

amit kumar

21.2k24 gold badges96 silver badges129 bronze badges