Converting table data to datetime

I have data in a .csv file. The second column contains time data. I want to convert it to datetime.

My code is:

tbldata=readtable('pipe2_st.csv');
tbldataarray=table2cell(tbldata);
data1 = tbldataarray (:,2);
t = datetime(data1,'InputFormat', '[HH:mm:ss.SSS]');

The data in 'data1' is:

{[01:05:17.319]}
{[01:05:17.328]}
{[01:05:17.338]}
{[01:05:17.347]}
{[01:05:17.357]}
{[01:05:17.365]}
{[01:05:17.385]}
{[01:05:17.394]}
{[01:05:17.403]}
{[01:05:17.412]}
{[01:05:17.422]}
{[01:05:17.432]}
{[01:05:17.441]}
{[01:05:17.450]}
{[01:05:17.460]}
{[01:05:17.469]}
{[01:05:17.478]}
{[01:05:17.488]}
{[01:05:17.497]}
{[01:05:17.506]}
{[01:05:17.516]}
{[01:05:17.525]}
{[01:05:17.534]}
{[01:05:17.544]}

It gives the error:

Error using datetime (line 672)
Input data must be a numeric array, a string array, a cell array containing character vectors, or a char matrix.

Kindly help in resolving the error.

[Stephen23]

@Kanica Sachdev: please upload the original CSV file by clicking the paperclip button.

Answer 1

[Cris LaPierre]

You need a date to make it a datetime (it will automatically use today if you don't supply one). Perhaps you want to use duration instead?

readtable should automatically read in the data as a duration, which has all the same benefits when it comes to tima as a datetime. There is no need to use table2cell. Instead, see how to access data in tables.

Coverting what you show as output to a csv file (attached), here is what my code would be.

tbldata=readtable('pipe2_st.csv')

tbldata = 24×1 table
        Var1    
    ____________

    01:05:17.319
    01:05:17.328
    01:05:17.338
    01:05:17.347
    01:05:17.357
    01:05:17.365
    01:05:17.385
    01:05:17.394
    01:05:17.403
    01:05:17.412
    01:05:17.422
    01:05:17.432
    01:05:17.441
    01:05:17.450
    01:05:17.460
    01:05:17.469

% Extract the Var1 variable from the table
tbldata.Var1

ans = 24×1 duration array
   01:05:17.319
   01:05:17.328
   01:05:17.338
   01:05:17.347
   01:05:17.357
   01:05:17.365
   01:05:17.385
   01:05:17.394
   01:05:17.403
   01:05:17.412
   01:05:17.422
   01:05:17.432
   01:05:17.441
   01:05:17.450
   01:05:17.460
   01:05:17.469
   01:05:17.478
   01:05:17.488
   01:05:17.497
   01:05:17.506
   01:05:17.516
   01:05:17.525
   01:05:17.534
   01:05:17.544

[Kanica Sachdev]

Thanks a lot for the help.

Answer 2

[dpb]

tbldata=readtable('pipe2_st.csv');
tbldataarray=table2cell(tbldata);

Don't convert the table to a cell array, use the table you've already got.....the form of the data output (a time string inside the square brackets all inside the curly braces) indicates readtable read the column as a duration variable already; you don't need to do anything with it other than perhaps combine it with the date ithat one presumes is in the first column.

I put the first few lines of your data above into a file with the above assumption...

>> tT=readtable('test.csv');
>> head(tT)
ans =
  8×1 table
        Var1    
    ____________
    01:05:17.319
    01:05:17.328
    01:05:17.338
    01:05:17.347
    01:05:17.357
    01:05:17.365
    01:05:17.385
    01:05:17.394
>> 

Then did the nasty thing of turning a perfectly good table into a cell array...

>> table2cell(ans)
ans =
  8×1 cell array
    {[01:05:17.319]}
    {[01:05:17.328]}
    {[01:05:17.338]}
    {[01:05:17.347]}
    {[01:05:17.357]}
    {[01:05:17.365]}
    {[01:05:17.385]}
    {[01:05:17.394]}
>>

That's where the artifacts of the {[...]} came from, you just didn't look at the content of the table variables themselves...

>> isduration(tT.Var1)
ans =
  logical
   1
>> 1