How can I read an hex number with dlmread? - matlab

Question

I'm trying to read a .csv file with Octave (I suppose it's equivalent on Matlab). One of the columns contains hexadecimal values identifying MAC addresses, but I'd like to have it parsed anyway, I don't mind if it's converted to decimal.
Is it possible to do this automatically with functions such as dlmread? Or do I have to create a custom function?
This is how the file looks like:
Timestamp, MAC, LastBsn, PRR, RSSI, ED, SQI, RxGain, PtxCoord, Channel: 26
759, 0x35c8cc, 127, 99, -307, 29, 237, 200, -32
834, 0x32d710, 183, 100, -300, 55, 248, 200, -32
901, 0x35c8cc, 227, 100, -300, 29, 238, 200, -32
979, 0x32d6a0, 22, 95, -336, 10, 171, 200, -32
987, 0x32d710, 27, 96, -328, 54, 249, 200, -32
1054, 0x35c8cc, 71, 92, -357, 30, 239, 200, -32
1133, 0x32d6a0, 122, 95, -336, 11, 188, 200, -32
I can accept any output value for the (truncated) MAC addresses, from sequence numbers (1-6) to decimal conversion of the value (e.g. 0x35c8cc -> 3524812).
My current workaround is to use a text editor to manually replace the MAC addresses with decimal numbers, but an automated solution would be handy.

Answer 1

The functions dlmread and csvread will handle numeric files. You can use textscan (which is also present in Matlab), but since you're using Octave, you're better off using csv2cell (part of Octave's io package). It basically reads a csv file and returns a cell array of strings and doubles:
octave-3.8.1> type test.csv
1,2,3,"some",1c:6f:65:90:6b:13
4,5,6,"text",0d:5a:89:46:5c:70
octave-3.8.1> plg load io; # csv2cell is part of the io package
octave-3.8.1> data = csv2cell ("test.csv")
data =
{
[1,1] = 1
[2,1] = 4
[1,2] = 2
[2,2] = 5
[1,3] = 3
[2,3] = 6
[1,4] = some
[2,4] = text
[1,5] = 1c:6f:65:90:6b:13
[2,5] = 0d:5a:89:46:5c:70
}
octave-3.8.1> class (data{1})
ans = double
octave-3.8.1> class (data{9})
ans = char

Answer 2

>> type mycsv.csv
Timestamp, MAC, LastBsn, PRR, RSSI, ED, SQI, RxGain, PtxCoord, Channel: 26
759, 0x35c8cc, 127, 99, -307, 29, 237, 200, -32
834, 0x32d710, 183, 100, -300, 55, 248, 200, -32
901, 0x35c8cc, 227, 100, -300, 29, 238, 200, -32
979, 0x32d6a0, 22, 95, -336, 10, 171, 200, -32
987, 0x32d710, 27, 96, -328, 54, 249, 200, -32
1054, 0x35c8cc, 71, 92, -357, 30, 239, 200, -32
1133, 0x32d6a0, 122, 95, -336, 11, 188, 200, -32
You can read the file with csv2cell. The values starting with "0x" will be automatically converted from hex to decimal values. See:
>> pkg load io % load io package for csv2cell
>> data = csv2cell ("mycsv.csv");
>> data(2,1)
ans =
{
[1,1] = 759
}
To access the cell values use:
>> data{2,1}
ans = 759
>> data{2,2}
ans = 3524812
>> data{2,5}
ans = -307