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ExcelWriter does not have the ability to render a PivotTable, so any modifications made to a PivotTable will not take affect until the output file is opened in Excel and the PivotTable is refreshed. If RefreshOnOpen is true, Excel will refresh the PivotTable when the workbook opens, which will re-render the PivotTable.
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3. Add PivotTableFields
Next, add PivotTableFields to the PivotTable. There are four types of PivotTableField: DataFields, RowLabels, ColumnLabels, and PageFields (or report filters). The Pivot field properties are available for all four types of PivotTableField, however some properties will not have an affect, depending on the type of field. These properties can be read and written to, but they will be ignored by Excel.
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