Re: How do I manipulate that data?
- To: mathgroup at smc.vnet.net
- Subject: [mg22481] Re: [mg22403] How do I manipulate that data?
- From: "David Park" <djmp at earthlink.net>
- Date: Sat, 4 Mar 2000 02:26:46 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Mark,
Here is a small data list:
data = {{1, 1}, {2, 2}, {3, 3}};
For small sets, this will work:
data /. {x_, y_} -> {x, y^2}
{{1, 1}, {2, 4}, {3, 9}}
For very large set you might want to use this:
Transpose[MapAt[#1^2 & , Transpose[data], 2]]
{{1, 1}, {2, 4}, {3, 9}}
Or this:
({#1[[1]], #1[[2]]^2} & ) /@ data
{{1, 1}, {2, 4}, {3, 9}}
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
>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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