Lua 中的表是一组具有唯一键的键值映射。这些对以任意顺序存储,因此表不以任何方式排序。
你能做的是iterate按某种顺序在桌子上。基础的pairs
不保证您访问键的顺序。这是一个定制版本pairs
,我称之为spairs
因为它按排序顺序迭代表:
function spairs(t, order)
-- collect the keys
local keys = {}
for k in pairs(t) do keys[#keys+1] = k end
-- if order function given, sort by it by passing the table and keys a, b,
-- otherwise just sort the keys
if order then
table.sort(keys, function(a,b) return order(t, a, b) end)
else
table.sort(keys)
end
-- return the iterator function
local i = 0
return function()
i = i + 1
if keys[i] then
return keys[i], t[keys[i]]
end
end
end
这是使用此类函数的示例:
HighScore = { Robin = 8, Jon = 10, Max = 11 }
-- basic usage, just sort by the keys
for k,v in spairs(HighScore) do
print(k,v)
end
--> Jon 10
--> Max 11
--> Robin 8
-- this uses an custom sorting function ordering by score descending
for k,v in spairs(HighScore, function(t,a,b) return t[b] < t[a] end) do
print(k,v)
end
--> Max 11
--> Jon 10
--> Robin 8