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python – How to write big set of data to xls file?

Posted by: admin March 9, 2020 Leave a comment


I have really big database which I want write to xlsx/xls file. I already tried to use xlwt, but it allows to write only 65536 rows (some of my tables have more than 72k rows). I also found openpyxl, but it works too slow, and use huge amount of memory for big spreadsheets. Are there any other possibilities to write excel files?

Following kennym’s advice i used Optimised Reader and Writer. It is less memory consuming now, but still time consuming. Exporting takes more than hour now (for really big tables- up to 10^6 rows). Are there any other possibilities? Maybe it is possible to export whole table from HDF5 database file to excel, instead of doing it row after row– like it is now in my code?

How to&Answers:

Try and use XlsxWriter in Constant Memory mode.

For .xls files I fear there’s no memory optimized way. Did you find any ?


Use the Optimized Reader and Writer of the openpyxl package. The optimized reader and writer run much faster and use far less memory than the standard openpyxl methods.


XlsxWriter work for me. I try openpyxl but it error. 22k*400 r*c