# Help fitting and selecting data?

Posted 2 months ago
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 Kindly find the data:https://drive.google.com/file/d/1Zw_GBnhFYbEglEKzTXnCv4o5xEMMT9n1/view?usp=sharingI want to fit my data. After using drop and select, I am getting blank {}. I want to fit my data of XZ Plane and potential. Kindly help, as soon as possible
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Posted 2 months ago
 Hi Soumyaranjan,This is an empty list, so all of the data is being filtered out, so DataxzStein is empty. Select[DataxyzStein, -10^-7 <= #[[2]] <= 10^-7 &] There are four columns in the data which columns are x, y, z? What is the fourth column?
Posted 2 months ago
 Extract columns 1, 3, 4 DataxzStein = DataxyzStein[[All, {1, 3, 4}]] FittXZStein = NonlinearModelFit[ DataxzStein, {ModelxzStein}, {Subscript[T, 0], Subscript[T, 2], Subscript[T, 4], Subscript[T, 6], Subscript[T, 8], Subscript[T, 10]}, {x, z}] FittXZStein["RSquared"] (* 0.9845 *) FittXZStein["ParameterTable"] 
Posted 2 months ago
 Something like this? (* MinMax for x, y, z, p *) MinMax /@ Transpose@DataxyzStein (* {{-0.495, 0.495}, {-0.495, 0.495}, {-0.305, 0.305}, {0.299106, 0.998006}} *) (* Select positive x values *) DataxzSteinPosX = Select[DataxzStein, #[[1]] >= 0 &] MinMax /@ Transpose@DataxzSteinPosX (* {{0.005, 0.495}, {-0.305, 0.305}, {0.302262, 0.998001}} *) 
Posted 2 months ago
 Hi Rohit !! 1st 3 columns are x, y and z, respectively. The 4t one is the Electric Potential which is a function of x, y and z. Since I want to fit in the XZ plane, so I want to drop the y column. Please help me to fit those data. Thank you for your time and consideration.
Posted 2 months ago
 Hi Rohit,Thank you so much for your time and consideration. But let's say I want to extract a specific range of data from my column data points for fitting; how to do that?Sorry for the silly question. For a beginner, I am struggling to learn. It would be helpful if you answer this. Regards, Soumyaranjan
 Add whatever filtering on values you want (* In DataxzStein, x is column 1 and z is column 2 *) DataxzSteinSubset = Select[DataxzStein, Between[#[[1]], {-0.32, 0.32}] && Between[#[[2]], {-0.22, 0.22}] &] MinMax /@ Transpose@DataxzSteinSubset (* {{-0.315, 0.315}, {-0.215, 0.215}, {0.447852, 0.889891}} *) Use DataxzSteinSubset to fit.