Re: Select from list
- To: mathgroup at smc.vnet.net
- Subject: [mg61060] Re: Select from list
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Sun, 9 Oct 2005 01:35:10 -0400 (EDT)
- Organization: The Open University, Milton Keynes, U.K.
- References: <di7r7c$koa$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Steven Taracevicz wrote:
> hi:
>
> I read a text file that gives me a list.
> nLevel[8, 10] = Import["output8_10.txt", "List"]
>
> {-10,-9,-7,-3,1,3,3,17}
>
> I have no problems calculating mean, variance etc. with the list.
>
> When I use:
>
> Select[nLevel[8,10], #<0]
>
> yields
>
> {}
>
> despite negative elements.
>
> I cannot figure out why.
>
> Thanks,
>
Hi Steven,
A pure function MUST end with the symbol '&', that is the test #<0 must
be written "# < 0 &" (without the quotes or double quotes). For instance
In[1]:=
data = {-10, -9, -7, -3, 1, 3, 3, 17};
Select[data, #1 < 0 & ]
Out[2]=
{-10, -9, -7, -3}
Best regards,
/J.M.