分割字符串

 1local ngx_find    = ngx.re.find
 2
 3local function split(str, sep , count)
 4    local t = {}
 5    count = count or -1
 6
 7    local nfield, nstart = 1, 1
 8    local nfirst,nlast = string.find(str, sep)
 9    -- local nfirst,nlast = ngx_find(str, sep, "jo")
10    while nfirst and count ~= 0 do
11        t[nfield] = string.sub(str, nstart, nfirst - 1)
12        nfield = nfield+1
13        nstart = nlast+1
14        nfirst,nlast = string.find(str, sep, nstart)
15        -- nfirst,nlast = ngx_find(str, sep, "jo", nil, nstart)
16        count = count-1
17    end
18    t[nfield] = string.sub(str, nstart)
19    return t
20end

保留小数后n位

1local function round(num, n)
2    local p = math.pow(10, n or 3)
3    local m = num * p
4    local _, d = math.modf(m)
5    if d < 0.5 then return math.floor(m) / p end
6    return math.ceil(m) / p
7end

随机字符串

https://gist.github.com/haggen/2fd643ea9a261fea2094