Find the value at exact location in a text file

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Yasemin Eldayih Kanber on 29 Mar 2021

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Commented: Yasemin Eldayih Kanber on 3 Aug 2021

Hello,

I have a huge text file which has coordinates and the pressure values for each location. I need to find the pressure values for exact locations. Is anyone know how to do it?

Any and all help would be greatly appreiciated. Thank you!

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Mathieu NOE on 29 Mar 2021

hi

maybe you should share your data file and explain which data you're looking for

Yasemin Eldayih Kanber on 30 Mar 2021

Edited: per isakson on 30 Mar 2021

Hi,

Below is the part of the file that I have. It has 2,800,000 lines and for example I would like to find bold data(look the end.) For a specific coordinate I need to find P value.

Thank you!

x y z p

-9.9500000E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-9.8500001E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-9.7500002E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-9.6500003E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-9.5499998E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-9.4499999E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-9.3500000E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-9.2500001E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-9.1500002E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-9.0499997E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-8.9499998E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-8.8499999E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-8.7500000E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-8.6500001E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-8.5500002E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-8.4500003E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-8.3499998E-01 4.9999999E-03 9.4999999E-02 1.2254493E+05

-8.2499999E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-8.1500000E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-8.0500001E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-7.9500002E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-7.8499997E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-7.7499998E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-7.6499999E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-7.5500000E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-7.4500000E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-7.3500001E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-7.2500002E-01 4.9999999E-03 9.4999999E-02 1.2254494E+05

-7.1500003E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-7.0499998E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.9499999E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.8500000E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.7500001E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.6500002E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.5499997E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.4499998E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.3499999E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.2500000E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.1500001E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-6.0500002E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-5.9500003E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-5.8499998E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-5.7499999E-01 4.9999999E-03 9.4999999E-02 1.2254495E+05

-5.6500000E-01 4.9999999E-03 9.4999999E-02 1.2254496E+05

-5.5500001E-01 4.9999999E-03 9.4999999E-02 1.2254496E+05

-5.4500002E-01 4.9999999E-03 9.4999999E-02 1.2254496E+05

-5.3499997E-01 4.9999999E-03 9.4999999E-02 1.2254496E+05

-5.2499998E-01 4.9999999E-03 9.4999999E-02 1.2254496E+05

-5.1499999E-01 4.9999999E-03 9.4999999E-02 1.2254496E+05

-5.0500000E-01 4.9999999E-03 9.4999999E-02 1.2254497E+05

-4.9500000E-01 4.9999999E-03 9.4999999E-02 1.2254497E+05

-4.8500001E-01 4.9999999E-03 9.4999999E-02 1.2254497E+05

-4.7499999E-01 4.9999999E-03 9.4999999E-02 1.2254497E+05

-4.6500000E-01 4.9999999E-03 9.4999999E-02 1.2254497E+05

-4.5499998E-01 4.9999999E-03 9.4999999E-02 1.2254497E+05

-4.4499999E-01 4.9999999E-03 9.4999999E-02 1.2254497E+05

-4.3500000E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-4.2500001E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-4.1499999E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-4.0500000E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.9499998E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.8499999E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.7500000E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.6500001E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.5500002E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.4500000E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.3500001E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.2499999E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.1500000E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-3.0500001E-01 4.9999999E-03 9.4999999E-02 1.2254498E+05

-2.9500002E-01 4.9999999E-03 9.4999999E-02 1.2254499E+05

-2.8500000E-01 4.9999999E-03 9.4999999E-02 1.2254499E+05

-2.7500001E-01 4.9999999E-03 9.4999999E-02 1.2254499E+05

-2.6499999E-01 4.9999999E-03 9.4999999E-02 1.2254499E+05

-2.5500000E-01 4.9999999E-03 9.4999999E-02 1.2254499E+05

-2.4500000E-01 4.9999999E-03 9.4999999E-02 1.2254499E+05

-2.3500000E-01 4.9999999E-03 9.4999999E-02 1.2254499E+05

-2.2499999E-01 4.9999999E-03 9.4999999E-02 1.2254499E+05

-2.1500000E-01 4.9999999E-03 9.4999999E-02 1.2254499E+05

-2.0500000E-01 4.9999999E-03 9.4999999E-02 1.2254500E+05

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Answer 1

Mathieu NOE on 30 Mar 2021

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https://uk.mathworks.com/matlabcentral/answers/786436-find-the-value-at-exact-location-in-a-text-file#answer_662234

Open in MATLAB Online

readclm.m

hello

hope this helps

I used the attached function to load the data (FYI)

% demo 
clc
clearvars;
% load data 
[outdata,head] = readclm('data_ya.txt',4,1);
% 
x_target = -3.1500000E-01;
y_target = 4.9999999E-03;
z_target = 9.4999999E-02;
tol = eps;
ind_x= find(abs(outdata(:,1) - x_target)< tol);
ind_y= find(abs(outdata(:,2) - y_target)< tol);
ind_z= find(abs(outdata(:,3) - z_target)< tol);
% find common single unique value accross ind_x / ind_y / ind_z
indxy_intersect = intersect(ind_x,ind_y);
indxz_intersect = intersect(ind_x,ind_z);
indxyz_intersect = intersect(indxy_intersect,indxz_intersect);
result_P  = outdata(indxyz_intersect,4);

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Answer 2

per isakson on 30 Mar 2021

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Edited: per isakson on 31 Mar 2021

Open in MATLAB Online

An alternative construct based on ismembertol(). I believe it's faster.

%%
fid = fopen( 'cssm.txt', 'rt' );  % cssm.txt contains the data provided in the question
cac = textscan( fid, '%f%f%f%f', 'Headerlines',1, 'CollectOutput',true );
[~] = fclose( fid );
num = cac{1};
%%
ism = ismembertol(  num(:,1:3)                                      ...
                ,   [-3.1500000E-01,4.9999999E-03,9.4999999E-02]    ...
                ,   1                                               ...
                ,   'DataScale' , [1e-8,1e-10,1e-9]                 ...
                ,   'ByRows'    , true                              );
format long            
pressure  = num( ism, 4 )

outputs

pressure =
     1.225449800000000e+05
>> 

Caveat: I don't understand this example from the documentation

Example: [LIA,LocB] = ismembertol(A,B,'ByRows',true,'DataScale',[eps(1) eps(10) eps(100)])

The values of 'DataScale' together with the default value of tol, 1e-12, doesn't make sense to me. That's why I explicitely set tol = 1.

In response to comment

"I have 69 points" ismembertol() handles multiple "points" nicely. Replace the second section of my script by (I just copy&pasted the two rows following your bold row.)

%%
ism = ismembertol(  num(:,1:3)                                      ...
                ,   [ -3.1500000E-01,4.9999999E-03,9.4999999E-02    
                      -3.0500001E-01,4.9999999E-03,9.4999999E-02
                      -2.9500002E-01,4.9999999E-03,9.4999999E-02 ]  ...
                ,   1                                               ...
                ,   'DataScale' , [1e-8,1e-10,1e-9]                 ...
                ,   'ByRows'    , true                              );
format long  
locations = find( ism )
pressure  = num( ism, 4 )

and you get

locations =
    69
    70
    71
pressure =
   1.0e+05 *
   1.225449800000000
   1.225449800000000
   1.225449900000000
>> 

Are all 2,800,000 locations unique?

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Answer 3

Yasemin Eldayih Kanber on 31 Mar 2021

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Thank you for all answers. What if I have 69 points, not only one?

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per isakson on 31 Mar 2021

See my answer

Yasemin Eldayih Kanber on 3 Aug 2021

Hello, I am getting this error.

pressure =

0×1 empty double column vector

Do you know how to solve it?

Thanks

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Find the value at exact location in a text file

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