www.gusucode.com > datastoreio工具箱 matlab源码程序 > datastoreio/+matlab/+io/+datastore/@SpreadsheetDatastore/hasdata.m
function tf = hasdata(ds) %HASDATA Returns true if there is more data in the SpreadsheetDatastore. % TF = hasdata(SSDS) returns true if there is more data in the % SpreadsheetDatastore SSDS, and false otherwise. read(SSDS) issues an % error when hasdata(SSDS) returns false. % % Example: % -------- % % Create a SpreadsheetDatastore % ssds = spreadsheetDatastore('airlinesmall_subset.xlsx') % % We are only interested in the Arrival Delay data % ssds.SelectedVariableNames = 'ArrDelay' % % Preview the first 8 rows of the data as a table % tab8 = preview(ssds) % % Sum the Arrival Delays % sumAD = 0; % ssds.ReadSize = 'sheet'; % while hasdata(ssds) % tab = read(ssds); % data = tab.ArrDelay(~isnan(tab.ArrDelay)); % filter data % sumAD = sumAD + sum(data); % end % sumAD % % See also - matlab.io.datastore.SpreadsheetDatastore, hasdata, readall, preview, reset. % Copyright 2015 The MathWorks, Inc. % return true if there is already data available for conversion or if there % are more splits with data which can be converted. try tf = ds.IsDataAvailableToConvert || hasdata@matlab.io.datastore.FileBasedDatastore(ds); catch ME throw(ME); end end