How to modify Google Docs table cells using CSV data with placeholder detection

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1

I’m trying to populate a table in Google Docs using data from a CSV file. The table has a fixed structure with 3 columns and initially contains 2 rows. I need to locate the table by finding a specific placeholder {{marker}} within it.

I’m running into two main problems:

  1. Getting this error: "Invalid requests[0].insertTableRow: Invalid table start location. Must specify the start index of the table."
  2. When I fix the above issue, only the first cell gets updated instead of all cells

I think the problem is in my data replacement logic. Here’s my current approach:

def populate_doc_table(doc_id, file_data):
    api_service = setup_google_docs()
    doc = api_service.documents().get(documentId=doc_id).execute()
    doc_body = doc.get('body', {})
    elements = doc_body.get('content', [])
    operations = []

    target_table = None
    for item in elements:
        if 'table' in item:
            current_table = item['table']
            for table_row in current_table['tableRows']:
                for table_cell in table_row['tableCells']:
                    for cell_content in table_cell['content']:
                        for text_element in cell_content['paragraph']['elements']:
                            if 'textRun' in text_element and '{{marker}}' in text_element['textRun'].get('content', ''):
                                target_table = text_element
                                break
                        if target_table:
                            break
                if target_table:
                    break
            if target_table:
                break

    if not target_table:
        print("Cannot find table containing placeholder '{{marker}}'")
        return

    start_position = target_table['startIndex']
    required_rows = len(file_data)

    # Add necessary rows to table
    for _ in range(required_rows):
        operations.append({
            'insertTableRow': {
                'tableCellLocation': {
                    'tableStartLocation': {
                        'index': start_position
                    },
                    'rowIndex': len(current_table['tableRows']) - 1
                },
                'insertBelow': True
            }
        })

    # Fill cells with CSV content
    for row_num, data_row in enumerate(file_data):
        for col_num, (field, value) in enumerate(data_row.items()):
            operations.append({
                'insertText': {
                    'location': {
                        'index': start_position + row_num * len(data_row) + col_num
                    },
                    'text': value
                }
            })

    # Apply all changes
    if operations:
        request_body = {'requests': operations}
        result = api_service.documents().batchUpdate(documentId=doc_id, body=request_body).execute()
        print('Table modification complete:', result.get('replies'))

I need all rows and columns in the table to be properly filled with the CSV data. What am I doing wrong with the index calculation?

2

Your problem is calculating text positions wrong in Google Docs tables. When you find the placeholder text, you’re using its startIndex as the table start - but that’s just pointing to a text run inside a cell, not the actual table.

I hit this same issue building a document automation tool last year. You need to track the actual table object and calculate cell positions from the table structure, not individual text elements.

Your start_position + row_num * len(data_row) + col_num approach assumes linear text layout, but tables are way more complex - they’ve got nested structures with paragraph elements in each cell.

Better approach: first clear existing content in target cells by deleting text ranges, then insert new content at the correct paragraph start positions within each cell. You’ll need to traverse the table structure again during population to get accurate cell positions instead of trying to calculate them mathematically.

3

You’re mixing up table structure identification with text insertion positions. When you find the placeholder text, you’re storing a reference to the text run instead of the actual table.

I ran into this same problem building a contract generation system. Here’s the thing: tableStartLocation needs to reference the table’s structural position in the document, not text inside it. Store item['startIndex'] from the table element, not text_element['startIndex'] from the placeholder text.

Your cell filling logic won’t work either - it assumes sequential text positions, but Google Docs tables don’t work that way. Each cell has paragraph elements that need individual addressing. Don’t try calculating positions with math. Instead, iterate through the actual table rows and cells again during population, using each cell’s paragraph start index for text insertion.

Try this: delete the existing text range first, then insert new content at the same position.

4

you’re grabbing the wrong index completely. when you find that {{marker}} text, you’re storing the textRun element but you actually need the table element’s startIndex. also, that math formula for positions is completely broken - google docs doesn’t work like a flat text file where you can just add numbers to find cell positions.