16 468
contributi
Differenze tra le versioni di "Modulo:Wikilib/tables"
Jump to navigation
Jump to search
m
Added groupBy
(Genral refactoring: added zip, flatten, values and new slice functionality *** sovrascritto il testo esistente ***) |
m (Added groupBy) |
||
|
end
t.zip = table.zip
--[[
Returns a table from a source, grouping elements by a function value. The items
of the new table are tables, each corresponding to a group. Groups are
determined by the return value of a function: the result is used as a key for
the group table, that contains all the elements of the passed table that
returned that value.
The getGroup function takes an element and its key, in this order: in fact, the
key is often unnecessary, and would just clutter the code in these cases.
--]]
table.groupBy = function(tab, getGroup, iter)
iter = iter or pairs
local groups = {}
for k, v in iter(tab) do
local groupID = getGroup(v)
if not groups[groupID] then
groups[groupID] = {}
end
table.insert(groups[groupID], v)
end
return groups
end
t.groupBy = table.groupBy
return t
| |||