From d8a1608160263ecc43f5623e9cefe860a499042d Mon Sep 17 00:00:00 2001 From: Jean Privat Date: Mon, 4 Dec 2017 08:59:27 -0500 Subject: [PATCH] core: add `Sequence::get_or_default` and `get_or_null` Signed-off-by: Jean Privat --- lib/core/collection/abstract_collection.nit | 30 +++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/lib/core/collection/abstract_collection.nit b/lib/core/collection/abstract_collection.nit index 309d048..04dabfa 100644 --- a/lib/core/collection/abstract_collection.nit +++ b/lib/core/collection/abstract_collection.nit @@ -859,6 +859,36 @@ interface SequenceRead[E] end end + # Try to get an element, return `null` if the `index` is invalid. + # + # ~~~ + # var a = [10,20,30] + # assert a.get_or_null(1) == 20 + # assert a.get_or_null(3) == null + # assert a.get_or_null(-1) == null + # assert a.get_or_null(-10) == null + # ~~~ + fun get_or_null(index: Int): nullable E + do + if index >= 0 and index < length then return self[index] + return null + end + + # Try to get an element, return `default` if the `index` is invalid. + # + # ~~~ + # var a = [10,20,30] + # assert a.get_or_default(1, -1) == 20 + # assert a.get_or_default(3, -1) == -1 + # assert a.get_or_default(-1, -1) == -1 + # assert a.get_or_default(-10, -1) == -1 + # ~~~ + fun get_or_default(index: Int, default: E): E + do + if index >= 0 and index < length then return self[index] + return default + end + # Get the last item. # Is equivalent with `self[length-1]`. # -- 1.7.9.5