How to convert 24-bit signed hex from .csv file to an array of decimal data?

14 vues (au cours des 30 derniers jours)
Neo
Neo le 23 Juil 2019
Commenté : Neo le 23 Juil 2019
The csv file has content like below, the hexical data is signed 24-bit and has 0x prefix:
============
DATA
0xfd22cc
0xfe89d1
0xff8d8b
0x004b41
0x00d9d5
0x0125fa
==============
I have a few challenges, not quite good with coding with Matlab:
1) How to get rid of 0x prefix?
2) How to convert the signed 24-bit hex to decimal?
I came up with a really ugly code to do the work, but would love to learn a elegant way:
%% Read in data
dat = readtable('demo.csv');
dat1 = table2array(dat(:,1));
out = strip(dat1,'left','0');
out = strip(out,'left','x');
out_dec = typecast(uint32(base2dec(out, 16)), 'int32');
for i=1:length(out_dec)
if out_dec(i) < 2^23
out_signed(i) = out_dec(i);
else
out_signed(i) = out_dec(i) - 2^24;
end
end

Réponse acceptée

Jan
Jan le 23 Juil 2019
dataTable = readtable('demo.csv');
data = table2array(dataTable(:,1));
data = strrep(data, '0x', '');
dataDec = base2dec(data, 16);
index = dataDec >= 2^23;
dataDec(index) = dataDex(index) - 2^24;
I prefer the faster sscanf to convert hex strings to decimals.
  2 commentaires
Guillaume
Guillaume le 23 Juil 2019
Note that:
data = table2array(dataTable(:,1));
is simply:
data = dataTable{:, 1};
%or
data = dataTable.(1);
%or
data = dataTable.Data;
Neo
Neo le 23 Juil 2019
very helpful, thanks.

Connectez-vous pour commenter.

Plus de réponses (1)

Guillaume
Guillaume le 23 Juil 2019
Modifié(e) : Guillaume le 23 Juil 2019
I agree with Jan that sscanf is nicer and for that reason:
dataTable = readtable('demo.csv');
dataDec = rowfun(@(s) sscanf(s, '%x'), dataTable, 'ExtractCellContents', true, 'OutputFormat', 'uniform')
dataDec(dataDec > 2^23) = dataDec(dataDec > 2^23) - 2^24;

Catégories

En savoir plus sur Data Type Conversion dans Help Center et File Exchange

Produits

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by