Re: How do I manipulate that data?
- To: mathgroup at smc.vnet.net
- Subject: [mg22457] Re: How do I manipulate that data?
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Sat, 4 Mar 2000 02:26:29 -0500 (EST)
- References: <89iaoe$msi@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Mark,
My tmp file looks like
!! tmp
0.341719 0.990566
0.505954 0.28635
0.663925 0.309206
Read it in, as you do,
data = ReadList["tmp", {Real, Real}]
{{0.341719, 0.990566}, {0.505954, 0.28635}, {0.663925, 0.309206}}
Square the second entry in each row
data /. {{x_Real, y_Real} :> {x, y^2}}
{{0.341719, 0.981221}, {0.505954, 0.0819963}, {0.663925, 0.0956084}}
It's probably better to get the raw data in this case, but we can use
ReadList["tmp", Unevaluated[{#1, #2^2} &[Real, Real]]]
{{0.341719, 0.981221}, {0.505954, 0.0819963}, {0.663925, 0.0956084}}
Allan
---------------------
Allan Hayes
Mathematica Training and Consulting
Leicester UK
www.haystack.demon.co.uk
hay at haystack.demon.co.uk
Voice: +44 (0)116 271 4198
Fax: +44 (0)870 164 0565
"mark griggs" <markgriggs at sc.rr.com> wrote in message
news:89iaoe$msi at smc.vnet.net...
> Hello all,
> I have a data file called data.txt. It consists of 2 columns of
> data. I am able to read with
> data = ReadList["/home/mark/data.txt", {Real, Real}]; I let the first
> column represent x and the second represent y. Then I plot y vs. x
> with ListPlot[data]. My problem is that I need to plot y^2 vs. x.
> So, how can I square all the y terms?
>
> regards
>
> mark
>
>
>
>
> --
> Heisenburg may have slept here
> ------------------------------
>
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