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Re: How do I test for existence of a list element?

• To: mathgroup at smc.vnet.net
• Subject: [mg112674] Re: How do I test for existence of a list element?
• From: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>
• Date: Sun, 26 Sep 2010 02:43:26 -0400 (EDT)
• References: <i7k4d7$lha$1@smc.vnet.net>

You could test whether the index you are using is larger than the
length of the list using Length[ ], but it would seem like bad
programming if such an index could accidentally pop up.

Cheers -- Sjoerd

On Sep 25, 8:21 am, Joseph Gwinn <joegw... at comcast.net> wrote:
> I have an application where I am bouncing around in a list, and may
> accidentally ask for an element beyond the end of the list, which causes
> Mathematica to complain and balk, preventing completion.
>
> Is there any way to test for the existence of a list element without
> provoking complaint or balking should the list item fail to exist?
>
> Thanks,
>
> Joe Gwinn