Performance issues with readtable vs. xlsread
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I am working in R2020a and have converted the Excel file read in one of my MATLAB scripts from xlsread to readtable, since xlsread is now deprecated.
However, I am having performance issues with readtable compared to xlsread.
The Excel file is a 15MB .xlsb file with six sheets, and I am using named ranges to locate the data on the approrpriate sheet.
tic; [perforations, perforations_header] = xlsread(xls_file,sheet,'PERFORATIONS'); toc
Elapsed time is 4.354259 seconds.
tic; T=readtable(xls_file,'Sheet',sheet,'Range','PERFORATIONS'); toc
Elapsed time is 15.777517 seconds.
perforations = table2array(T); perforations_header=T.Properties.VariableNames; toc
Elapsed time is 15.803216 seconds.
So, two questions:
(1) Any suggestions on how to improve performance for readtable?
(2) Despite xlsread being deprecated, it clearly performs better than readtable. Is there any downside with staying with xlsread?
My thanks!
Mike
P.s. Attached is a cut down version of the Excel .xlsb file. It contains two named ranges: 'PERFORATIONS' and 'CELLS'. The full file was too large to attach.
2 个评论
Walter Roberson
2020-12-3
Consider experimenting with readtable() with the 'UseExcel', true flag.
Mike
2020-12-3
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Star Strider
2020-12-2
0 个投票
If you need to use xlsread, use it as long as you have it available.
Since you obviously want the header information as well, one option could be to use readtable once to read everything in once (likely using 'VariableNamingRule','preserve' in your call to it), perhaps extracting the variable names separately as <tablename>.Properties.VariableNames to a cell, then using save to put all the information you want in a .mat file. Then load the .mat file as necessary to retrieve the necessary information into your workspace. Either save the headers and data separately as different variables, or save it as a table.
I have no idea how efficient this would be, since I have no idea what your Excel file contains, or how large it is. It is simply an option to consider.
2 个评论
Star Strider
2020-12-3
My pleasure!
My idea is to read them in once with readtable, save them to .mat files, then load them as necessary when you need them later.
If a function is deprecated, it will not be supported (and will likely not appear) beginning in some future release, although code using it may still work. (It’s complicated!)
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