Determine if tall array data is of specified class



tf = isaUnderlying(X,cl) returns a tall array containing logical 1 (true) if the underlying data in tall array X is of class cl. Otherwise, the tall array contains logical 0 (false).


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All tall tables and arrays belong to the tall class. However, the underlying data type of a tall array can vary.

Create a datastore for the airlinesmall.csv data set. Select a subset of the variables to work with, and treat 'NA' values as missing data so that datastore replaces them with NaN values. Convert the datastore into a tall table.

varnames = {'Year', 'UniqueCarrier'};
ds = tabularTextDatastore('airlinesmall.csv','TreatAsMissing','NA',...
tt = tall(ds)
tt =

  Mx2 tall table

    Year    UniqueCarrier
    ____    _____________

    1987       {'PS'}    
    1987       {'PS'}    
    1987       {'PS'}    
    1987       {'PS'}    
    1987       {'PS'}    
    1987       {'PS'}    
    1987       {'PS'}    
    1987       {'PS'}    
     :            :
     :            :

Test whether the underlying data type of the first table variable Year is single.

tf = isaUnderlying(tt.Year,'single')
tf =

  tall logical


Determine the actual underlying data type of Year.

udt = classUnderlying(tt.Year)
udt =

  1x6 tall char array


Input Arguments

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Input array, specified as a tall array.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | table | cell | categorical | datetime | duration | calendarDuration

Underlying class, specified as a character vector specifying any valid MATLAB® class name.

Example: tf = isaUnderlying(X,'double')


Extended Capabilities

Tall Arrays
Calculate with arrays that have more rows than fit in memory.

Introduced in R2016b