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Question

我正在开发一个非常大的程序，它再次从一个非常大的 excel 电子表格中获取数据。由于某些奇怪的原因，加载这个大 excel 文件需要很长时间，我希望以某种方式加快它的速度。我做了自己的研究并尝试了 read_only，但这并没有让我读取任何单元格（至少如下所示的方式）。非常欢迎任何建议。

def LoadSheet(Filename,worksheet_nr):
    import time as t
    st = t.clock()
    wb = xl.load_workbook(str(Filename))#workbook, loading workbook
    Sheets = wb.get_sheet_names()#Worksheets, shows all sheets in the workbook loaded
    ActiveSheet = wb.get_sheet_by_name(Sheets[worksheet_nr])#Selects the first sheet
    print round(t.clock() - st,3), "seconds of loading time."
    print "Sheet is loaded and reading..."
    return ActiveSheet



def CountRC_nr(ActiveSheet, StartR,StartC):
    R = StartR#Selected starting Row number
    C = StartC#Selected starting Column number
    Val = None #Value in cell (Right now, none is selected, thus zero value)
    while (Val != "None"):
        Val = str(ActiveSheet.cell(row=R,column=C).value)
        R += 1

    NumberRows = R - StartR - 1
    Val = None
    R=StartR

    while (Val != "None"):
        Val = str(ActiveSheet.cell(row=R,column=C).value)
        C += 1
    NumberColumns = C - StartC - 1

    return NumberRows, NumberColumns

由于有人要求看我如何使用read_only，这里修改代码：

def LoadSheet(Filename,worksheet_nr):
    import time as t
    st = t.clock()
    wb = xl.load_workbook(str(Filename), read_only = True)#workbook, loading workbook
    Sheets = wb.get_sheet_names()#Worksheets, shows all sheets in the workbook loaded
    ActiveSheet = wb.get_sheet_by_name(Sheets[worksheet_nr])#Selects the first sheet
    print round(t.clock() - st,3), "seconds of loading time."
    print "Sheet is loaded and reading..."
    return ActiveSheet



def CountRC_nr(ActiveSheet, StartR,StartC):
    R = StartR#Selected starting Row number
    C = StartC#Selected starting Column number
    Val = None #Value in cell (Right now, none is selected, thus zero value)
    while (Val != "None"):
        Val = str(ActiveSheet.cell(row=R,column=C).value)
        R += 1

    NumberRows = R - StartR - 1
    Val = None
    R=StartR

    while (Val != "None"):
        Val = str(ActiveSheet.cell(row=R,column=C).value)
        C += 1
    NumberColumns = C - StartC - 1

    return NumberRows, NumberColumns

Answer 1

正如我已经说过的，您正在与 API 作对。如果工作表的维度已知，那么您可以访问它们，否则您可以构建自己的计数器，这没什么意义。

只读模式对于单个查找非常快，但由于每个查找涉及解析行中的所有单元格直到感兴趣的单元格，因此对于很多人来说效率非常低它们，例如您的代码正在使用。

wb = load_workbook(filename, read_only=True)
for ws in wb:
    print(ws.dimensions)
    for row in ws.rows:
         for cell in row:
             print(cell.value)  # do whatever you want with the cell

您可以使用 (cell.value for cell in row) 轻松地将行转换为 NumPy 数组，但 Pandas 库还将工作表直接读取到数据框中。

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