How to import a 50mb csv file?
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I have a csv file of size 50mb. The data is numbers and strings. I tried to import it using the import button in matlab. Now the data is 100% parsed but nothing happens for an hour, I think it's still working. It took more than 6 hours to parse 100%. Is there a smarter and faster way to import the data and save it as a matrix?
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Walter Roberson
am 27 Jun. 2018
We recommend using readtable(). Especially if you have R2016b or later, in which case use detectImportOptions first to create an options structure to pass to readtable() .
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Walter Roberson
am 27 Jun. 2018
If you need to end up with a matrix, then table2cell() . You cannot use table2array() because you have mixed data types.
If you want to create arrays of the various parts that are alike, then
raw = table2cell(YourTable);
mask = cellfun(@isnumeric, raw(1,:));
num = cell2mat( raw(:,mask) );
mask = cellfun(@ischar, raw(1,:));
txt = raw(:,mask);
Here I make the assumption that all entries in a column are the same data type. This will not necessarily be true if you used readtable() with empty cells or text-based indicators of missing data such as "NA" that do not happen to match "nan" or "NaN" -- though if you used detectImportOptions then it should notice those by itself, and you can also use the TreatAsEmpty option to readtable.
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