Openpyxl 1.8.5: Reading the result of a formula typed in a cell using openpyxl

Question

I am printing some formula in one of the Excel sheets:

wsOld.cell(row = 1, column = 1).value = "=B3=B4"

But I cannot use its result in implementing some other logic, as:

if((wsOld.cell(row=1, column=1).value)='true'):
    # copy the 1st row to another sheet

Even when I am trying to print the result in the command line, I end up printing the formula:

>>> print(wsOld.cell(row=1, column=1))
>>> =B3=B4

How can I get the result of the formula in a cell and not the formula itself?

Asked By: ravikant

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Source

Answer 1

openpyxl support either the formula or the value of the formula. You can select which using the data_only flag when opening a workbook. However, openpyxl does not and will not calculate the result of a formula. There are libraries out there like pycel which purport to do this.

Answered By: Charlie Clark

Answer 2

Openpyxl doesn’t support excel 100% for calculating the formula. It supports only very basic formulas. If you want to calculate all formula in workbook you should use xlwings library (which is supported on MacOS and Windows only).

Answered By: vidur-88

Answer 3

I have solved the matter using a combination of openpyxl and pandas:

import pandas as pd
import openpyxl
from openpyxl import Workbook , load_workbook


source_file = "Test.xlsx"
# write to file
wb = load_workbook (source_file)
ws = wb.active
ws.title = "hello world"
ws.append ([10,10])
wb.save(source_file)

# read from file
df = pd.read_excel(source_file)
sum_jan = df ["Jan"].sum() 
print (sum_jan)

Answered By: rainer

Answer 4

xlwings, PyXll FlyingKoala, DataNitro all use Excel as the interface to using Python.

If you want to use a Python library you can try PyCel, xlcalculator, Formulas and Schedula.

I am the project owner of xlcalculator.

xlcalculator uses openpyxl to read Excel files and adds functionality which translates Excel formulas into Python.

An example using xlcalculator with an Excel file:

from xlcalculator import ModelCompiler
from xlcalculator import Model
from xlcalculator import Evaluator

filename = r'use_case_01.xlsm'
compiler = ModelCompiler()
new_model = compiler.read_and_parse_archive(filename)
evaluator = Evaluator(new_model)
val1 = evaluator.evaluate('First!A2')
print("value 'evaluated' for First!A2:", val1)

An example using xlcalculator with a dict;

input_dict = {
    "B4": 0.95,
    "B2": 1000,
    "B19": 0.001,
    "B20": 4,
    # B21
    "B22": 1,
    "B23": 2,
    "B24": 3,
    "B25": "=B2*B4",
    "B26": 5,
    "B27": 6,
    "B28": "=B19*B20*B22",
    "C22": "=SUM(B22:B28)",
  }

from xlcalculator import ModelCompiler
from xlcalculator import Model
from xlcalculator import Evaluator

compiler = ModelCompiler()
my_model = compiler.read_and_parse_dict(input_dict)
evaluator = Evaluator(my_model)

for formula in my_model.formulae:
    print("Formula", formula, "evaluates to", evaluator.evaluate(formula))

# cells need a sheet and Sheet1 is default.
evaluator.set_cell_value("Sheet1!B22", 100)
print("Formula B28 now evaluates to", evaluator.evaluate("Sheet1!B28"))
print("Formula C22 now evaluates to", evaluator.evaluate("Sheet1!C22"))

Answered By: bradbase

Openpyxl 1.8.5: Reading the result of a formula typed in a cell using openpyxl

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