# Lookup values in other table that has a range of values

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Daniel Goldstein le 14 Fév 2022
Commenté : Daniel Goldstein le 14 Fév 2022
I've got two data sets from a drilling project collected by different sensors.
One table has rate of penetration at the recorded depths. The other has wireline gamma values for the same hole but at different recorded depths.
Rate of Penetration data set
holeid = [12;12;12;12;12;12;12;12;12;12;12;12;12;12;12;12];
depth = [0;0.0542;0.0801;0.2222;0.3959;0.4572;0.5110;0.5348;0.5712;0.6099;0.6437;0.6799;0.8011;0.8928;0.9590;1.0110];
rop = [118.7000;207.8000;139.6000;176.0000;177.8000;229.3000;242.4000;138.9000;85.7000;140.8000;164.5000;125.4000;189.8000;164.0000;118.4000;211.4000];
rophole12 = table(holeid,depth,rop);
Gamma data set
(e.g. depth from 0 to 0.13 is treated as from/to range and has gamma value of 1, depth of 0.13 to 0.22 has gamma value of 12, etc)
holeid1 = [12;12;12;12;12;12;12;12;12;12;12;12;12];
depth1 = [0;0.13;0.22;0.36;0.48;0.56;0.67;0.78;0.84;0.96;1.03;1.14;1.24;];
gamma1 = [1;12;34;23;42;12;43;67;111;200;153;188;55];
gammahole12 = table(holeid1,depth1,gamma1);
What's the best way to get the gamma values from gammahole12 at the depths specified in the rophole12 table e.g. gamma at 0, 0.0542, 0.0801, etc?
In excel, I've used the vlookup function with true. Is there a MATLAB equivalent or different way to lookup a value within a different table with approximate reference, e.g. depth in this case?
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### Réponse acceptée

AndresVar le 14 Fév 2022
Modifié(e) : AndresVar le 14 Fév 2022
Something like this would add the gamma variable to your first table, BUT it's matching to nearest gamma
rophole12.gamma = interp1(gammahole12.depth1,gammahole12.gamma1,rophole12.depth,'nearest')
See: 1-D data interpolation (table lookup) - MATLAB interp1 (mathworks.com) for other matching options such as next or previeous
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Cris LaPierre le 14 Fév 2022
Using 'previous' seems to give the same results as vlookup.
holeid = [12;12;12;12;12;12;12;12;12;12;12;12;12;12;12;12];
depth = [0;0.0542;0.0801;0.2222;0.3959;0.4572;0.5110;0.5348;0.5712;0.6099;0.6437;0.6799;0.8011;0.8928;0.9590;1.0110];
rop = [118.7000;207.8000;139.6000;176.0000;177.8000;229.3000;242.4000;138.9000;85.7000;140.8000;164.5000;125.4000;189.8000;164.0000;118.4000;211.4000];
rophole12 = table(holeid,depth,rop);
holeid1 = [12;12;12;12;12;12;12;12;12;12;12;12;12];
depth1 = [0;0.13;0.22;0.36;0.48;0.56;0.67;0.78;0.84;0.96;1.03;1.14;1.24;];
gamma1 = [1;12;34;23;42;12;43;67;111;200;153;188;55];
gammahole12 = table(holeid1,depth1,gamma1);
% Use interp1 with method set to 'previous' to get same result as vlookup
% (for this example, at least)
rophole12.gamma = interp1(gammahole12.depth1,gammahole12.gamma1,rophole12.depth,'previous')
rophole12 = 16×4 table
holeid depth rop gamma ______ ______ _____ _____ 12 0 118.7 1 12 0.0542 207.8 1 12 0.0801 139.6 1 12 0.2222 176 34 12 0.3959 177.8 23 12 0.4572 229.3 23 12 0.511 242.4 42 12 0.5348 138.9 42 12 0.5712 85.7 12 12 0.6099 140.8 12 12 0.6437 164.5 12 12 0.6799 125.4 43 12 0.8011 189.8 67 12 0.8928 164 111 12 0.959 118.4 111 12 1.011 211.4 200
Daniel Goldstein le 14 Fév 2022
Previous works better for this purpose but good to be aware of the nearest and next options too. Thank you!

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### Plus de réponses (1)

Cris LaPierre le 14 Fév 2022
Modifié(e) : Cris LaPierre le 14 Fév 2022
Another way that seems to also give the results you would get with vlookup is with discretize.
holeid = [12;12;12;12;12;12;12;12;12;12;12;12;12;12;12;12];
depth = [0;0.0542;0.0801;0.2222;0.3959;0.4572;0.5110;0.5348;0.5712;0.6099;0.6437;0.6799;0.8011;0.8928;0.9590;1.0110];
rop = [118.7000;207.8000;139.6000;176.0000;177.8000;229.3000;242.4000;138.9000;85.7000;140.8000;164.5000;125.4000;189.8000;164.0000;118.4000;211.4000];
rophole12 = table(holeid,depth,rop);
holeid1 = [12;12;12;12;12;12;12;12;12;12;12;12;12];
depth1 = [0;0.13;0.22;0.36;0.48;0.56;0.67;0.78;0.84;0.96;1.03;1.14;1.24;];
gamma1 = [1;12;34;23;42;12;43;67;111;200;153;188;55];
gammahole12 = table(holeid1,depth1,gamma1);
% Use discretize to find the corresponding 'bin' gamma value
rophole12.gamma = discretize(rophole12.depth,[gammahole12.depth1;inf],gammahole12.gamma1)
rophole12 = 16×4 table
holeid depth rop gamma ______ ______ _____ _____ 12 0 118.7 1 12 0.0542 207.8 1 12 0.0801 139.6 1 12 0.2222 176 34 12 0.3959 177.8 23 12 0.4572 229.3 23 12 0.511 242.4 42 12 0.5348 138.9 42 12 0.5712 85.7 12 12 0.6099 140.8 12 12 0.6437 164.5 12 12 0.6799 125.4 43 12 0.8011 189.8 67 12 0.8928 164 111 12 0.959 118.4 111 12 1.011 211.4 200
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Daniel Goldstein le 14 Fév 2022
Thank you for multiple solutions. They are fantastic!

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