The AttributeError: 'MergedCell' object attribute 'value' is read-only error occurs when you try to assign a value to a read-only attribute of a MergedCell object in Python.
In Python, MergedCell objects represent merged cells in a spreadsheet. These cells have a combined value from all the cells they span. However, the value attribute of a MergedCell object is read-only, meaning you cannot modify it directly.
Here’s an example to help understand this error:
# Import the necessary library
from openpyxl import Workbook
# Create a new workbook
wb = Workbook()
# Select the active worksheet
ws = wb.active
# Merge cells A1 to B1
ws.merge_cells('A1:B1')
# Access the merged cell object
merged_cell = ws['A1']
# Try to assign a new value to the merged cell
merged_cell.value = "New Value" # This will raise the AttributeError
# Save the workbook
wb.save("example.xlsx")
In the example above, we create a new workbook and select the active worksheet. We then merge cells A1 to B1 using the merge_cells() method. After that, we try to assign a new value to the merged cell using the value attribute, which results in the AttributeError.
To overcome this error, you need to modify the values of the individual cells that make up the merged cell rather than directly modifying the merged cell itself. Here’s an updated example:
# Import the necessary library
from openpyxl import Workbook
# Create a new workbook
wb = Workbook()
# Select the active worksheet
ws = wb.active
# Merge cells A1 to B1
ws.merge_cells('A1:B1')
# Access the individual cells in the merged range
for cell in ws['A1:B1']:
cell.value = "New Value"
# Save the workbook
wb.save("example.xlsx")
In the updated example, we still merge cells A1 to B1 and access the individual cells in that range using a loop. We then assign the desired value to each individual cell, effectively updating the value for the merged cell as a whole.