Re: Plotting from a file
- To: mathgroup at smc.vnet.net
- Subject: [mg33141] Re: [mg33108] Plotting from a file
- From: Timothy Stiles <tastiles at students.wisc.edu>
- Date: Tue, 5 Mar 2002 03:08:46 -0500 (EST)
- References: <200203031130.GAA06263@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
I think your first problem is addressed in the following FAQ http://support.wolfram.com/mathematica/kernel/files/fortran.html which describes how to set up Mathematica 4.0 to accept the exponential notation with Import. I often use a completely different method namely data = ReadList["datafile.dat", Number, RecordLists->True]; which is left over from the pre version 4.0 days which didn't have an Import[] command. To suppress output in Mathematica end a command with a semicolon (as in the above command). This will keep Mathematica from printing the entire file. Finally, to plot your data, you have to use Mathematica syntax not Matlab. To plot a list, you need to use the ListPlot[] command (Plot[] plots function directly). The argument of ListPlot[] can be in any of several forms, a single list will be treated as y-values with x-values assumed to be the list {1, 2, 3, ..., n}. You can specify the y and x-values by using a list of {x, y} pairs like ListPlot[{{x1, y1}, {x2, y2}, ... {xn, yn}}]. Hope this helps. Tim Stiles SuneF wrote: > Hi > > I have this output file of floating point data from a C program. > It is all printed in 1.435664334e-013 notation, 7 columns in total. > > When I import with: > data=Import["datafile.dat","Table"] > it doesn't understand the exponential notation. > It's printing the whole file (huge file by the way) below the command and > only a handfull of the floats seem to be understood correctly as 1.333^10-13. > If I print the numbers as 0.00000001234 then mathematica understands, > but this is not ideal, obviously. > > Also, later when it works I need to plot the columns, something like > Plot[data(2,*)] > you know, plot the second column. > The code doesn't work, mathematica doesn't take arrays like that, not sure why. > > I'm very confused about why mathematica have both lists, arrays and matrices, > I don't know what to work with in this case. > > Is it possible to declare a datatype like in C++ ? > I like to know what I'm working with, call it force of habbit ;) > > Thanks, > Sune.
- References:
- Plotting from a file
- From: "SuneF" <noluck@nowhere.dk>
- Plotting from a file