RE: How to check for key existence in a table (for the lazy programmer)?
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- Subject: RE: How to check for key existence in a table (for the lazy programmer)?
- From: "Charles Melice" <3d@...>
- Date: 2015年1月31日 14:48:10 +0100
I think it is possible to prepare this test on previous assignement.
Otherwise only I see this solution:
local function eval( chunk )
local f = load('return '..chunk)
local ok, ret = pcall(f)
return ok and ret or nil
end
local v = eval' host.devices.bridge.friendlyName'
if v then
...
end
Charles
> -----Message d'origine-----
> De : lua-l-bounces@lists.lua.org [mailto:lua-l-bounces@lists.lua.org] De
> la part de Bertrand Mansion
> Envoyé : samedi 31 janvier 2015 11:45
> À : Lua mailing list
> Objet : How to check for key existence in a table (for the lazy
> programmer)?
>
> In Lua programs, I often see code like the following:
>
> if host.devices and host.devices.bridge and
> host.devices.bridge.friendlyName then
>
> In Php, I have seen this:
>
> if (isset($host['devices']['bridge']['friendlyName']))
>
>
> In Python, I have seen this:
>
> try:
> if host['devices']['bridge']['friendlyName']:
> ...
> except KeyError:
> pass
>
> Are there other ways in Lua to check for a key existence ?