Help removing columns from csv file

Hey all,

I'm new to matlab and need some quick help manipulating csv files. I have giant (1 million rows plus) csv files with 6 columns, and I need to run PSDs on only two of the columns of data. I want to extract the two specific columns of data from the big csv, put them into variables or separate csvs, and use them for calculations. Right now I'm wrestling with textscan because there are headers in these files and some of the columns contain text.

Sample of data:

Ct*0.00127405S  A1(g)  A2(g)  A3(g)  SN  FCTR  
1  0.027  -0.022  0.985  95  41  [Crc OK]
2  0.027  -0.022  0.985  95  42  [Crc OK]
3  0.027  -0.022  0.984  95  43  [Crc OK]
4  0.027  -0.021  0.982  95  44  [Crc OK]
5  0.027  -0.022  0.983  95  45  [Crc OK]

thank you! JT

Answer 1

[John]

If you want to load in the data and pull out the third and fourth columns (just as an example) I'd do the following:

[num txt raw] = xlsread('Book1.csv');
data = cell2mat(raw(2:end,[3 4]));
csvwrite('test.csv',data)

This will pull the data out and save it into a new csv file, you could also try,

[num txt raw] = xlsread('Book1.csv');
data = num(2:end,[3 4]);
csvwrite('test.csv',data)

If you dont want to mess with cell arrays, hope it helps.

[Jimes Tooper]

this is great, except it doesn't work on macs :D

luckily i have a pc lying around too!

thanks John!

[John]

Forgot about that, thanks, if youre on mac you might want to try csvread() although this only can only import numerical data (no strings in the file).

[John]

On a mac you may also be able to use importdata

A = importdata('Book1.csv')

and then index however you like