Re: Setting Negatives to Zero
- To: mathgroup at smc.vnet.net
- Subject: [mg82822] Re: [mg82736] Setting Negatives to Zero
- From: Carl Woll <carlw at wolfram.com>
- Date: Wed, 31 Oct 2007 06:25:03 -0500 (EST)
- References: <200710300826.DAA13428@smc.vnet.net>
Kevin J. McCann wrote:
>I have a very large data set (64000 x 583) in which negative values
>indicate "no data", unfortunately these negatives are not all the same.
>I would like to efficiently set all these negatives to zero. I know that
>I will likely be embarrassed when I see how to do it, but I can't seem
>to remember or figure it out. I should emphasize that because of the
>size of the data set, this needs to be done efficiently. Another
>programming language does it as follows:
>
> x(x < 0) = 0;
>
>Thanks,
>
>Kevin
>
>
I think the fastest approach will be to use the function Clip:
Clip[data, {0, Infinity}]
By the way, I discussed some methods for efficiently programming tasks
like yours in Mathematica in my talk at the 2007 Wolfram Technology
Conference, which you can find at:
http://library.wolfram.com/infocenter/Conferences/7005/
Carl Woll
Wolfram Research
- References:
- Setting Negatives to Zero
- From: "Kevin J. McCann" <Kevin.McCann@umbc.edu>
- Setting Negatives to Zero