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: Sun, 5 Mar 2000 00:24:16 -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 >------------------------------ > > > >