Variable Names not being read into uitable using readmatrix

Hi, I am trying to read a csv files into a uitable and am having problems reading the variable names in. The csv was saved using writetable and the first few lines are here:

Idx,pos,sep1,sep2,avgsep,deltaPix
1,101.1,1799.918,1868.078,1833.998,0.769999999999
2,101.2,1801.527,1868.695,1835.111,1.88299999999
3,101.3,1802.028,1869.09,1835.559,2.3309999999
4,101.4,1801.645,1869.739,1835.692,2.46399999999
5,101.5,1802.023,1869.453,1835.738,2.50999999999

This is my code to read the file :

              table=app.UItable;
              C=readtable(fullpath,'VariableNamingRule','preserve','FileType','text'); 
              C=table2array(C);             % Wasn't sure if I needed this
              opts = detectImportOptions(fullpath)
              opts.VariableNames
              ReportMessage(app,'Opened Successfully')
              table.Data=C;  

Its not reading in the variable name

The opts.variablenames is showing the variable names are present

              ans =
              
              1×6 cell array
              
              {'Idx'}    {'pos'}    {'sep1'}    {'sep2'}    {'avgsep'}    {'deltaPix'}

and opts is:

              opts = 
              
              DelimitedTextImportOptions with properties:
              
              Format Properties:
              Delimiter: {','}
              Whitespace: '\b\t '
              LineEnding: {'\n'  '\r'  '\r\n'}
              CommentStyle: {}
              ConsecutiveDelimitersRule: 'split'
              LeadingDelimitersRule: 'keep'
              TrailingDelimitersRule: 'ignore'
              EmptyLineRule: 'skip'
              Encoding: 'UTF-8'
              
              Replacement Properties:
              MissingRule: 'fill'
              ImportErrorRule: 'fill'
              ExtraColumnsRule: 'addvars'
              
              Variable Import Properties: Set types by name using setvartype
              VariableNames: {'Idx', 'pos', 'sep1' ... and 3 more}
                  VariableTypes: {'double', 'double', 'double' ... and 3 more}
                  SelectedVariableNames: {'Idx', 'pos', 'sep1' ... and 3 more}
                  VariableOptions: Show all 6 VariableOptions 
              	Access VariableOptions sub-properties using setvaropts/getvaropts
                VariableNamingRule: 'modify'
               

Any reason why the variable names aren't being populated into the uitable?

Thanks

Answer 1

[Voss]

Using C = table2array(C) makes C a numeric array rather than a table array. Numeric arrays only contain numbers (no information about column or row names), so that's why the uitable's ColumnName property does not change when you set the uitable's Data property. You'd have to set the ColumnName property separately, similar to this:

C = readtable(fullpath,'VariableNamingRule','preserve','FileType','text');
C = table2array(C);
app.UItable.Data = C;
app.UItable.ColumnName = C.Properties.VariableNames;

However, if you omit using table2array and set the uitable's Data to table array (rather than numeric array) C, then the ColumnName is updated automatically:

C = readtable(fullpath,'VariableNamingRule','preserve','FileType','text');
app.UItable.Data = C;

[Jason]

hmm, that still doesn't work for me

C.Properties.VariableNames
Dot indexing is not supported for variables of this type.

But this does work:

opts = detectImportOptions(fullpath);
opts.VariableNames
table.ColumnName = opts.VariableNames;

So if I was to leave the uitable data as "table" class rather than "double" by using table2array, is there any disadvantage? I need to perform calculations on each the data

[Voss]

"So if I was to leave the uitable data as "table" class rather than "double" by using table2array, is there any disadvantage?"

Not really, as long as you know how to deal with tables: https://www.mathworks.com/help/matlab/matlab_prog/access-data-in-a-table.html

"that still doesn't work for me"

What is the value of C immediately after

C = readtable(fullpath,'VariableNamingRule','preserve','FileType','text');

?

[Jason]

C =

  200×6 table

    Idx     pos      sep1      sep2     avgsep    deltaPix
    ___    _____    ______    ______    ______    ________

      1    101.1    1799.9    1868.1      1834       0.77 
      2    101.2    1801.5    1868.7    1835.1      1.883 
      3    101.3      1802    1869.1    1835.6      2.331 
      4    101.4    1801.6    1869.7    1835.7      2.464 

[Jason]

ahh, I think its because I didnt put it above the table2array conversion

C=readtable(fullpath,'VariableNamingRule', 'preserve')    %      C=readtable(fullpath,'VariableNamingRule', 'preserve','FileType','text');   
C.Properties.VariableNames
C=table2array(C);

It now works, thanks

(seems I may need to convert all my uitable data into tables as there's some nice tools / function to use with table (i.e. metadata, such as description ) :-)

[Voss]

Glad it's working!