add example for appendix c

Author: driscollis

appendix_c_formulas/summing.py

@@ -0,0 +1,31 @@
+# summing.py
+
+from openpyxl import Workbook
+
+
+def main(filename):
+    workbook = Workbook()
+    sheet = workbook.active
+
+    # Add data to spreadsheet
+    data_rows = [
+        ["Book", "Kindle", "Paperback"],
+        [1, 9.99, 15.99],
+        [2, 9.99, 25.99],
+        [3, 9.99, 25.99],
+        [4, 4.99, 29.99],
+        [5, 14.99, 39.99],
+    ]
+
+    for row in data_rows:
+        sheet.append(row)
+
+    # Sum up columns
+    sheet["A7"] = "Totals"
+    sheet["B7"] = "=SUM(B2:B6)"
+    sheet["C7"] = "=SUM(C2:C6)"
+    workbook.save(filename)
+
+
+if __name__ == "__main__":
+    main("summing.xlsx")