removing quotes from table

Hi,

I have a table with gregorian time that loads as having single quotes around it. This is giving me issues when I want to do table2timetable.

How do I remove the quotes so I can convert to timetable?

Thanks!

Answer 1

[Cris LaPierre]

The quotes inidcate the values are character arrays, Convert your times to datetimes.to remove the quotes.

It's best to do that at the time you import your data.using import options.

opts = detectImportOptions('filename.txt');

opts = setvartype(opts, 'Time_UTCG_','datetime')

opts = setvartopts(opts,'Time_UTCG_','InputFormat','d MMM yyyy HH:mm:ss.SSS');

TT = readtimetable('filename.txt',opts)

There may be more. Please attach your file to your post using the paperclip icon for an answer tailored to your data.

You can also convert your table as is if you choose.

Time_UTCG_ = ['1 Jan 2025 00:00:00.000';'1 Jan 2025 00:01:00.000'];
T = table(Time_UTCG_)

T = 2x1 table
          Time_UTCG_       
    _______________________

    1 Jan 2025 00:00:00.000
    1 Jan 2025 00:01:00.000

T.Time_UTCG_ = datetime(T.Time_UTCG_,'InputFormat','d MMM yyyy HH:mm:ss.SSS')

T = 2x1 table
         Time_UTCG_     
    ____________________

    01-Jan-2025 00:00:00
    01-Jan-2025 00:01:00

[puccapearl]

Hi, thank you I've attached my .csv file called data. I'm still seeing issues with just this.

Also would it be easier to start with epoc seconds and convert to datetime?

I've attached a second file with Epoch seconds in data2 in case that is easier? Ultimately want it to be in timetable format.

Thanks so much for your help.

[Cris LaPierre]

It looks like your time is actually elapsed time. In that case, I would use a duration instead of a datetime. The date is meaningless unless there is more information you have not shared.

opts = detectImportOptions('data.csv');
opts = setvartype(opts,'Time_UTCG_','duration');
opts = setvaropts(opts,'Time_UTCG_','InputFormat','mm:ss.S');
data = readtable('data.csv',opts)

Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.

data = 16x4 table
    Time_UTCG_    A_deg_    E_deg_    R_km_
    __________    ______    ______    _____

     00:00.0      59.497    18.629    11051
     01:00.0      59.085    17.712    11021
     02:00.0       58.69    16.797    10993
     03:00.0      58.311    15.885    10968
     04:00.0      57.947    14.977    10945
     05:00.0      57.597    14.071    10923
     06:00.0      57.261    13.168    10904
     07:00.0      56.939    12.269    10887
     08:00.0       56.63    11.373    10872
     09:00.0      56.333    10.481    10860
     10:00.0      56.048     9.592    10850
     11:00.0      55.775     8.707    10842
     12:00.0      55.513     7.826    10836
     13:00.0      55.261     6.948    10832
     14:00.0      55.021     6.074    10831
     15:00.0       54.79     5.204    10832

Epoch seconds could also be used, but you must also define the epoch (starting date).Assuming that is Jan 1, 2025 (based on the data shown in your question), you could do this.

data2 = readtable('data2.csv')

Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.

data2 = 16x4 table
    Time_EpochSec_    A_deg_    E_deg_    R_km_
    ______________    ______    ______    _____

           0          59.497    18.629    11051
          60          59.085    17.712    11021
         120           58.69    16.797    10993
         180          58.311    15.885    10968
         240          57.947    14.977    10945
         300          57.597    14.071    10923
         360          57.261    13.168    10904
         420          56.939    12.269    10887
         480           56.63    11.373    10872
         540          56.333    10.481    10860
         600          56.048     9.592    10850
         660          55.775     8.707    10842
         720          55.513     7.826    10836
         780          55.261     6.948    10832
         840          55.021     6.074    10831
         900           54.79     5.204    10832

data2.Time_EpochSec_ = datetime(data2.Time_EpochSec_,'ConvertFrom','epochtime','Epoch','2025-01-01')

data2 = 16x4 table
       Time_EpochSec_       A_deg_    E_deg_    R_km_
    ____________________    ______    ______    _____

    01-Jan-2025 00:00:00    59.497    18.629    11051
    01-Jan-2025 00:01:00    59.085    17.712    11021
    01-Jan-2025 00:02:00     58.69    16.797    10993
    01-Jan-2025 00:03:00    58.311    15.885    10968
    01-Jan-2025 00:04:00    57.947    14.977    10945
    01-Jan-2025 00:05:00    57.597    14.071    10923
    01-Jan-2025 00:06:00    57.261    13.168    10904
    01-Jan-2025 00:07:00    56.939    12.269    10887
    01-Jan-2025 00:08:00     56.63    11.373    10872
    01-Jan-2025 00:09:00    56.333    10.481    10860
    01-Jan-2025 00:10:00    56.048     9.592    10850
    01-Jan-2025 00:11:00    55.775     8.707    10842
    01-Jan-2025 00:12:00    55.513     7.826    10836
    01-Jan-2025 00:13:00    55.261     6.948    10832
    01-Jan-2025 00:14:00    55.021     6.074    10831
    01-Jan-2025 00:15:00     54.79     5.204    10832

Of course, if you have the epoch and a duration, you could just add them together.

data.Time_UTCG_ = data.Time_UTCG_ + datetime(2025,1,1)

data = 16x4 table
         Time_UTCG_         A_deg_    E_deg_    R_km_
    ____________________    ______    ______    _____

    01-Jan-2025 00:00:00    59.497    18.629    11051
    01-Jan-2025 00:01:00    59.085    17.712    11021
    01-Jan-2025 00:02:00     58.69    16.797    10993
    01-Jan-2025 00:03:00    58.311    15.885    10968
    01-Jan-2025 00:04:00    57.947    14.977    10945
    01-Jan-2025 00:05:00    57.597    14.071    10923
    01-Jan-2025 00:06:00    57.261    13.168    10904
    01-Jan-2025 00:07:00    56.939    12.269    10887
    01-Jan-2025 00:08:00     56.63    11.373    10872
    01-Jan-2025 00:09:00    56.333    10.481    10860
    01-Jan-2025 00:10:00    56.048     9.592    10850
    01-Jan-2025 00:11:00    55.775     8.707    10842
    01-Jan-2025 00:12:00    55.513     7.826    10836
    01-Jan-2025 00:13:00    55.261     6.948    10832
    01-Jan-2025 00:14:00    55.021     6.074    10831
    01-Jan-2025 00:15:00     54.79     5.204    10832

[puccapearl]

Thank you Cris, very insightful.