From: "Procházka Lukáš Ing." <LPr@pontex.cz>
To: "mailing list for ConTeXt users" <ntg-context@ntg.nl>
Subject: Re: about table operation in lua-ConTeXt
Date: Mon, 13 Feb 2017 10:22:34 +0100 [thread overview]
Message-ID: <op.yvldnw163h68c7@lprx.pontex.local> (raw)
In-Reply-To: <1869AF30-88A8-4A4F-9959-7E92E9A9DAB4@me.com>
Hello,
tables in Lua are "shared" - there is one copy until you "deep copy" one to another.
Se comments bellow -
On Mon, 13 Feb 2017 06:50:38 +0100, Jeong Dal <haksan@me.com> wrote:
> Dear all,
>
> It may be a slight off topic.
> In the following example, I copied a table “m” to “tempM”, and remove the last row of tempM.
> Then the output is “ 2, 2”
> I checked the contents of tempM and m and found that they are same even though I didn’t touch m.
> I want to remove the last row of tempM while keeping the table m untouched.
> Please tell me how to do it.
>
> Thank you.
> Best regards,
>
> Dalyoung
>
> \startbuffer[test]
> \startluacode
> m = {{0, 2, 4},{2, 3 , 4}, {2, 2, -6}}
> local tempM = {} -- OK, 'tempM' and 'm' are different tables - try 'print(tempM, m)' - you'll get two addresses
>
> tempM = m -- Now, 'tempM' and 'm' will point to the same table - "the 'm' table"
-- The original 'tempM' table will be forgotten and removed during next garbage collection as there is no other reference to it
-- ('tempM' starts pointing to 'm', too)
> table.remove(tempM) -- Will remove from one
> context(#tempM, “, ” , #m) -- Obviously - both table point to the same object, try again 'print(tempM, m)'
> \stopluacode
> \stopbuffer
>
> \starttext
> getbuffer[test]
> \stoptext
Best regards,
Lukas
--
Ing. Lukáš Procházka | mailto:LPr@pontex.cz
Pontex s. r. o. | mailto:pontex@pontex.cz | http://www.pontex.cz | IDDS:nrpt3sn
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next prev parent reply other threads:[~2017-02-13 9:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.128.1486929767.14600.ntg-context@ntg.nl>
2017-02-13 5:50 ` Jeong Dal
2017-02-13 8:54 ` Henri Menke
2017-02-13 8:56 ` Hans Hagen
2017-02-13 9:22 ` Procházka Lukáš Ing. [this message]
[not found] <mailman.1.1486983601.29608.ntg-context@ntg.nl>
2017-02-13 14:03 ` Jeong Dal
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