readtimetable

Create timetable from file.

📝Syntax

TT = readtimetable(filename)
TT = readtimetable(filename, opts)
TT = readtimetable(..., Name, Value)

📥Input Arguments

Parameter	Description
filename	a string: filename source.
opts	nelson.io.text.DelimitedTextImportOptions object.
Name, Value	optional pairs such as RowTimes, StartTime, TimeStep, SampleRate, InputFormat, and text import options shared with readtable.

📤Output Arguments

Parameter	Description
TT	a timetable.

📄Description

readtimetable imports column-oriented delimited text data and returns a timetable.

Row times can be selected with RowTimes and a variable name, supplied with RowTimes and a time vector, generated from StartTime and SampleRate, or generated from StartTime and TimeStep.

If no row-time option is specified, the first datetime-compatible or duration-compatible variable is used as row times.

When a file column is used as row times, that column is removed from timetable data variables. When row times are supplied or generated, all file variables remain data variables.

Delimited text files are supported. Unsupported external formats raise an error.

JSON files (.json extension or 'FileType', 'json') are read as with readtable, with the same JSON name-value arguments or a nelson.io.json.JSONImportOptions object. The first datetime or duration variable gives the row times, unless a row-time option is specified.

💡Examples

Read a file and automatically detect the first time column.

Time = {'2024-01-01'; '2024-01-02'; '2024-01-03'};
Temperature = [12.5; 13.0; 11.75];
Pressure = [1012; 1014; 1011];
T = table(Time, Temperature, Pressure);
filename = [tempdir(), 'readtimetable_auto.csv'];
writetable(T, filename);
TT = readtimetable(filename)
TT.Properties.RowTimes

Select the row-time column by name.

Date = {'2024-01-01'; '2024-01-02'; '2024-01-03'};
Temperature = [12.5; 13.0; 11.75];
Pressure = [1012; 1014; 1011];
T = table(Date, Temperature, Pressure);
filename = [tempdir(), 'readtimetable_timevariable.csv'];
writetable(T, filename);
TT = readtimetable(filename, 'RowTimes', 'Date')
TT.Properties.VariableNames

Supply row times explicitly.

Temperature = [12.5; 13.0; 11.75];
Pressure = [1012; 1014; 1011];
T = table(Temperature, Pressure);
filename = [tempdir(), 'readtimetable_rowtimes.csv'];
writetable(T, filename);
rowTimes = seconds([10; 20; 30]);
TT = readtimetable(filename, 'RowTimes', rowTimes)
TT.Properties.RowTimes

Generate regular row times with StartTime and SampleRate.

Temperature = [12.5; 13.0; 11.75; 12.25];
T = table(Temperature);
filename = [tempdir(), 'readtimetable_samplerate.csv'];
writetable(T, filename);
TT = readtimetable(filename, 'StartTime', seconds(0), 'SampleRate', 0.5)
TT.Properties.RowTimes

Read a JSON file as a timetable:

TT = timetable(datetime(2024, 1, 1) + days(0:2)', [12.5; 13; 11.75], 'VariableNames', {'Temperature'}); f = [tempdir, 'timetable_json.json']; writetimetable(TT, f, 'PrettyPrint', false); fileread(f) TT2 = readtimetable(f)

🕔Version History

Version	Description
2.0.0	initial version
2.0.0	JSON files: read JSON data as a timetable.

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