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[added] tablex.collapse to reduce the dimensionality of a table; caveats on some edge case behaviour documented

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Max Cahill 2020-04-29 20:57:05 +10:00
parent 87cdb1fcb7
commit b91f4f1fcc
1 changed files with 27 additions and 4 deletions
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29
tablex.lua
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@ -242,10 +242,10 @@ end
function tablex.copy(t, deep_or_into)
assert(type(t) == "table", "table.copy - argument 't' must be a table")
local is_bool = type(deep_or_into) == "boolean"
local istablex = type(deep_or_into) == "table"
local is_table = type(deep_or_into) == "table"
local deep = (is_bool and deep_or_into) or istablex
local into = istablex and deep_or_into or {}
local deep = is_bool and deep_or_into or is_table
local into = is_table and deep_or_into or {}
for k, v in pairs(t) do
if deep and type(v) == "table" then
if type(v.copy) == "function" then
@ -269,6 +269,29 @@ function tablex.overlay(to, from)
return to
end
--collapse the first level of a table into a new table of reduced dimensionality
--will collapse {{1, 2}, 3, {4, 5, 6}} into {1, 2, 3, 4, 5, 6}
--useful when collating multiple result sets, or when you got 2d data when you wanted 1d data.
--in the former case you may just want to append_inplace though :)
--note that non-tabular elements in the base level are preserved,
-- but _all_ tables are collapsed; this includes any table-based types (eg a batteries.vec2),
-- so they can't exist in the base level
-- (... or at least, their non-ipairs members won't survive the collapse)
function tablex.collapse(t)
assert(type(t) == "table", "table.collapse - argument 't' must be a table")
local r = {}
for _, v in ipairs(t) do
if type(v) == "table" then
for _, v in ipairs(v) do
table.insert(r, v)
end
else
table.insert(r, v)
end
end
return r
end
--faster unpacking for known-length tables up to 8
--gets around nyi in luajit
--note: you can use a larger unpack than you need as the rest