lua table函数补充 lua table的扩展

lua table函数补充

-- lua table扩展

-- 返回table大小
table.size = function(t)
    local count = 0
    for _ in pairs(t) do
        count = count + 1
    end
    return count
end

--返回table的最大value
table.maxn = function(t)
    local maxn = nil
    for _, v in pairs(t) do
        if nil == maxn then
            maxn = v
        end
        if maxn < v then
            maxn = v
        end
    end
    return maxn
end

--返回table的最小value
table.minn = function(t)
    local min = nil
    for _, v in pairs(t) do
        if nil == min then
            min = v
        end
        if min > v then
            min = v
        end
    end
    return min
end

-- 判断table是否为空
table.empty = function(t)
    return not next(t)
end

-- 返回table索引列表
table.indices = function(t)
    local result = {}
    for k, v in pairs(t) do
        table.insert(result, k)
    end
    return result
end

-- 返回table值列表
table.values = function(t)
    local result = {}
    for k, v in pairs(t) do
        table.insert(result, v)
    end
    return result
end

-- 浅拷贝
table.clone = function(t, nometa)
    local result = {}
    if not nometa then
        setmetatable(result, getmetatable(t))
    end
    for k, v in pairs (t) do
        result[k] = v
    end
    return result
end

-- 深拷贝
table.copy = function(t, nometa)
    local result = {}

    if not nometa then
        setmetatable(result, getmetatable(t))
    end

    for k, v in pairs(t) do
        if type(v) == "table" then
            result[k] = table.copy(v, nometa)
        else
            result[k] = v
        end
    end
    return result
end

table.merge = function(dest, src)
    for k, v in pairs(src) do
        dest[k] = v
    end
end

table.random = function(tbl)
    local len = #tbl
    if len == 1 then
        return tbl
    end
    for i = 1, len do
        local ranOne = math.random(1, len+1-i)
        tbl[ranOne], tbl[len+1-i] = tbl[len+1-i],tbl[ranOne]
    end
    return tbl
end

table.contain = function(t, val)
    for _, v in pairs(t) do
        if v == val then
            return true
        end
    end
    return false
end

table.count = function(t, val)
    local cnt = 0
    for _, v in pairs(t) do
        if v == val then
            cnt = cnt + 1
        end
    end
    return cnt
end

table.sum = function(t)
    local s = 0
    for _, v in pairs(t) do
        s = s + v
    end
    return s
end

table.sub = function(t, start, count)
    local st = {}
    for i = 1, count do
        table.insert(st, t[start+i-1])
    end
    return st
end

table.findIdx = function(t, val)
    for k, v in ipairs(t) do
        if v == val then
            return k
        end
    end
    return -1
end

table.removeVal = function(t, val)
    for k, v in ipairs(t) do
        if v == val then
            return table.remove(t, k)
        end
    end
end

--用val填充table
table.fill = function(t, val, count)
    if not count then count = #t end
    for i = 1, count do
        t[i] = val
    end
    return t
end

table.shuffle = function(t)
    for i = #t, 2, -1 do
        local j = math.random(i)
        t[i], t[j] = t[j], t[i]
    end
    return t
end