Re: How do I take every 3rd number from a text file?
- To: mathgroup at smc.vnet.net
- Subject: [mg114231] Re: How do I take every 3rd number from a text file?
- From: truxton spangler <truxtonspangler29 at gmail.com>
- Date: Sun, 28 Nov 2010 06:52:47 -0500 (EST)
- References: <icqfve$m3o$1@smc.vnet.net>
On Nov 27, 7:37 pm, cubsfan334 <cubsfan... at gmail.com> wrote:
> Hi,
>
> I've been reading in text files using the following command:
>
> ReadList["file.txt", Word]
>
> However, now I only want to read in every 3rd number, starting with
> the valueI specify.
>
> For example, say I had these values:
>
> 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
>
> How would I read in every third number, starting with the second
> integer? So the result would look like this:
>
> 1, 4, 7
Assuming that the line above is actually a string: "0, 1, 2, 3, 4, 5,
6, 7, 8, 9" then use StringSplit and Take or Span, e.g.
tmp = ToExpression@StringSplit["0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ", ", "]
then
Take[tmp, {2, Length[tmp], 3}]
or
tmp[[2 ;; Length[tmp] ;; 3]]