Python xlrd.Book: how to close the files?

Question

I read 150 excel files in a loop, opening them with xlrd.open_workbook(), which returns a Book object. At the end, when I tried to umount

Answer 1

In case you open a workbook with on_demand = True for a more economic resource use (see here how does it work), you need to call release_resources() method at the end. As a minimal example:

import xlrd

book = xlrd.open_workbook('workbook.xls', on_demand = True)
sheet = book.sheet_by_index(0)
data = [[str(c.value) for c in sheet.row(i)] for i in xrange(sheet.nrows)]
book.release_resources()
del book