Comparison of two unequal length files.

I have two .csv files of unequal length. each file has two colomns and one has 50000 rows and other has 27000 rows. in this first colomn is of wavelengths and other is of intensity. I want to get data in which the wavelengths of both files are equal and also want corrsponding intensities. so how can i find it using program?

thanking you in advance.

Answer 1

[Jan]

1. Import the files. (Is this a part of your problem?)
2. Search the intersection of the common variable with the command intersect . The 2nd and 3rd output give you the overlapping indices.

[Devang Anadkat]

yes, thank you i got it. I got the first colomn of wavelengths which are common in both data files. but now i want to get the intensities corresponding to that wavelengths from both data files. so what should i do?

[Jan]

I do not know, how the intensities are represented. Did you mention, if you your data are matrices with a specific number pof columns? A small example would be useful. With some guessing:

A = [1; 3; 2; 17]   % 1st file
B = [0, 0.1; 1, 0.2; 2, 0.3; 3 0.4; 17, 0.5; 24, 0.6];  % 2nd file

[Common, iA, iB] = intersect(A, B(:, 1));
CommonIntesity   = B(iB, 2)
A(iA, 2)         = B(iB, 2)   % Maybe wanted...

[Devang Anadkat]

this is first file

4.0004000e+02 2.2576667e+03

4.0006000e+02 2.7194000e+03

4.0008000e+02 2.9347143e+03

4.0010000e+02 3.0555556e+03 &

this is second file

400.04 0.2702

400.05 0.27026

400.06 0.27031

400.07 0.27036

400.08 0.27041

in this both files first colomn is of wavelength and other one is of intensity. i got the wavelength which are same in both files say 400.04 400.06 etc.. but in both files intensity is different corresponding to that same wavelength. so now i want the table in which i got first colomn is of wavelength which are common in both file second colomn is of intensity which is in file 1 corresponding to common wavelength and 3rd colomn is of intensity which is in file 2.