From 1a02819a668b7ddaa68bafedf5ec53d5e56f6670 Mon Sep 17 00:00:00 2001
From: Simon Hirsig <shirsig@cloud-agent.com>
Date: Fri, 16 Oct 2015 13:25:31 +0200
Subject: [PATCH] added group by utility

---
 util.lua | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/util.lua b/util.lua
index 8347433..3c152d5 100644
--- a/util.lua
+++ b/util.lua
@@ -234,4 +234,18 @@ function Aux.util.money_string(money)
 			return format(GSC_1, c)
 		end
 	end
-end
\ No newline at end of file
+end
+
+function Aux.util.group_by(tables, keys)
+	local groups = {}
+	Aux.util.map(tables, function(table)
+		for _, group in ipairs(groups) do
+			if Aux.util.all(keys, function(key) table[key] == group[1][key] end) then
+				tinsert(group, table)
+				return
+			end
+		end
+		tinsert(groups, { table })
+	end)
+	return groups
+end