TabularTextDatastore

Datastore for tabular text files

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Description

TabularTextDatastore objects are associated with collections of text files containing column-oriented or tabular data. Tabular data is data that is arranged in a rectangular fashion with each row having the same number of entries. To create a TabularTextDatastore object, you can use the tabularTextDatastore function or the datastore function. TabularTextDatastore properties specify how data is formatted in the files, and how you want to access the data.

Create Object

Create TabularTextDatastore objects using the tabularTextDatastore function or the datastore function.

Properties

TabularTextDatastore Properties Access and modify TabularTextDatastore properties

Object Functions

hasdata Determine if data is available to read
numpartitions Number of partitions
partition Partition a datastore
preview Return subset of data from datastore
read Read data in datastore
readall Read all data in datastore
reset Reset datastore to initial state

Examples

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Open Script

Create a datastore from the sample file airlinesmall.csv, which contains tabular data.

ds = tabularTextDatastore('airlinesmall.csv','TreatAsMissing','NA');

View the variables in the datastore.

ds.VariableNames

ans =

  1×29 cell array

  Columns 1 through 5

    'Year'    'Month'    'DayofMonth'    'DayOfWeek'    'DepTime'

  Columns 6 through 10

    'CRSDepTime'    'ArrTime'    'CRSArrTime'    'UniqueCarrier'    'FlightNum'

  Columns 11 through 14

    'TailNum'    'ActualElapsedTime'    'CRSElapsedTime'    'AirTime'

  Columns 15 through 20

    'ArrDelay'    'DepDelay'    'Origin'    'Dest'    'Distance'    'TaxiIn'

  Columns 21 through 24

    'TaxiOut'    'Cancelled'    'CancellationCode'    'Diverted'

  Columns 25 through 28

    'CarrierDelay'    'WeatherDelay'    'NASDelay'    'SecurityDelay'

  Column 29

    'LateAircraftDelay'

Modify the SelectedVariableNames property to specify the variables of interest.

ds.SelectedVariableNames = {'Year','Month','Cancelled'};

Alternatively, you can specify the variables of interest when you create the datastore.

ds = tabularTextDatastore('airlinesmall.csv','TreatAsMissing','NA','SelectedVariableNames',{'Year','Month','Cancelled'});
Open Script

Create a datastore from the sample file airlinesmall.csv, which contains tabular data.

ds = tabularTextDatastore('airlinesmall.csv','TreatAsMissing','NA');

Specify the variables of interest.

ds.SelectedVariableNames = {'Year','Month','UniqueCarrier'};

View the SelectedFormats property.

ds.SelectedFormats

ans =

  1×3 cell array

    '%f'    '%f'    '%q'

The SelectedFormats property indicates that the Year and Month variables will be interpreted as columns of floating-point values, and the UniqueCarrier variable will be interpreted as a column of text.

Specify that the first two variables should be read as signed integers, and the third variable should be read as a categorical value by modifying the SelectedFormats property.

ds.SelectedFormats = {'%d','%d','%C'};

Preview the data.

T = preview(ds)

T = 

    Year    Month    UniqueCarrier
    ____    _____    _____________

    1987    10       PS           
    1987    10       PS           
    1987    10       PS           
    1987    10       PS           
    1987    10       PS           
    1987    10       PS           
    1987    10       PS           
    1987    10       PS

Related Examples

See Also

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Introduced in R2014b

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