remove character from csv file header

How can a file be opened, then remove a character and save the file?

The attached csv file , test.csv, contains the following data:

a,b,c,

1,2,3

4,5,6

7,8,9

I need to remove the comma at the end of the header in order to properly read column variable names using readtable().

Answer 1

[Walter Roberson]

You do not need to do that. There some other approaches you can take:

1) readtable() the file as-is. In R2018b at least, that will return a table with 3 variables named Var1, Var2, Var3 -- the original header will be gone . If you need to, you can assign the names to the Properties.VariableNames property of the table

2) Similar to the above, but you also

T = readtable('test.csv');
fid = fopen('test.csv', 'rt');
S = fgetl(fid);
fclose(fid);
varnames = regexp(S, ',', 'split);
varnames( cellfun(@isempty, varnames) ) = [];   %remove any trailing empty fields
T.Properties.VariableNames = matlab.lang.makeUniqueStrings(matlab.lang.makeValidName(varnames));

3) Use textscan() to read the file, either with or without bothering to extract the variable names

4) If you do not need the variable names,

csvread('test.csv', 1, 0)

The 1 tells it to skip 1 row; the 0 tells it to skip zero columns.

[Walter Roberson]

There is another option for R2016b or later:

filename = 'test.csv';
opt = detectImportOptions(filename);
opt.VariableDescriptionsLine = 1;
data = readtable(filename, opt);
data.Properties.VariableNames = matlab.lang.makeUniqueStrings(matlab.lang.makeValidName(data.Properties.VariableDescriptions));

Grotty, but functional.