From a6faa5b82d08a1894c5be15d15531497476ea5cb Mon Sep 17 00:00:00 2001 From: Vsevolod Stakhov Date: Tue, 26 Nov 2019 19:23:58 +0000 Subject: [Minor] Add `lua_util.nkeys` utility --- lualib/lua_util.lua | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'lualib') diff --git a/lualib/lua_util.lua b/lualib/lua_util.lua index bda8b0c02..207bdc0dc 100644 --- a/lualib/lua_util.lua +++ b/lualib/lua_util.lua @@ -422,6 +422,30 @@ end exports.list_to_hash = list_to_hash +--[[[ +-- @function lua_util.nkeys(table|gen, param, state) +-- Returns number of keys in a table (i.e. from both the array and hash parts combined) +-- @param {table} list numerically-indexed table or string, which is treated as a one-element list +-- @return {number} number of keys +-- @example +-- print(lua_util.nkeys({})) -- 0 +-- print(lua_util.nkeys({ "a", nil, "b" })) -- 2 +-- print(lua_util.nkeys({ dog = 3, cat = 4, bird = nil })) -- 2 +-- print(lua_util.nkeys({ "a", dog = 3, cat = 4 })) -- 3 +-- +--]] +local function nkeys(gen, param, state) + local n = 0 + if not param then + for _,_ in pairs(gen) do n = n + 1 end + else + for _,_ in fun.iter(gen, param, state) do n = n + 1 end + end + return n +end + +exports.nkeys = nkeys + --[[[ -- @function lua_util.parse_time_interval(str) -- Parses human readable time interval -- cgit v1.2.3