Simulate autofit column in xslxwriter

I recently ran into this same issue and this is what I came up with:

r = 0
c = 0
for x in list:
    worksheet.set_column('{0}:{0}'.format(chr(c + ord('A'))), len(str(x)) + 2)
    worksheet.write(r, c, x)
    c += 1

In my example r would be the row number you are outputting to, c would be the column number you are outputting to (both 0 indexed), and x would be the value from list that you are wanting to be in the cell.

the '{0}:{0}'.format(chr(c + ord('A'))) piece takes the column number provided and converts it to the column letter accepted by xlsxwriter, so if c = 0 set_column would see 'A:A', if c = 1 then it would see 'B:B', and so on.

the len(str(x)) + 2 piece determines the length of the string you are trying to output then adds 2 to it to ensure that the excel cell is wide enough as the length of the string does not exactly correlate to the width of the cell. You may want to play with rather you add 2 or possibly more depending on your data.

The units that xlsxwriter accepts is a little harder to explain. When you are in excel and you hover over where you can change the column width you will see Width: 8.43 (64 pixels). In this example the unit it accepts is the 8.43, which I think is centimeters? But excel does not even provide a unit, at least not explicitly.

Note: I have only tried this answer on excel files that contain 1 row of data. If you will have multiple rows, you will need to have a way to determine which row will have the ‘longest’ information and only apply this to that row. But if each column will be roughly the same size regardless of row, then this should work fine for you.

Good luck and I hope this helps!

I agree with Cole Diamond. I needed to do something very similar, it worked fine for me. where self.columns is my list of columns

def set_column_width(self):
    length_list = [len(x) for x in self.columns]
    for i, width in enumerate(length_list):
        self.worksheet.set_column(i, i, width)

There is another workaround to simulate Autofit that I’ve found on the Github site of xlsxwriter. I’ve modified it to return the approximate size of horizontal text (column width) or 90° rotated text (row height):

from PIL import ImageFont

def get_cell_size(value, font_name, font_size, dimension="width"):
    """ value: cell content
        font_name: The name of the font in the target cell
        font_size: The size of the font in the target cell """
    font = ImageFont.truetype(font_name, size=font_size)
    (size, h) = font.getsize(str(value))
    if dimension == "height":
        return size * 0.92   # fit value experimentally determined
    return size * 0.13       # fit value experimentally determined

This doesn’t address bold text or other format elements that might affect the text size. Otherwise it works pretty well.

To find the width for your columns for autofit:

def get_col_width(data, font_name, font_size, min_width=1):
    """ Assume 'data' to be an iterable (rows) of iterables (columns / cells)
    Also, every cell is assumed to have the same font and font size.
    Returns a list with the autofit-width per column """
    colwidth = [min_width for col in data[0]]
    for x, row in enumerate(data):
        for y, value in enumerate(row):
            colwidth[y] = max(colwidth[y], get_cell_size(value, font_name, font_size))
    return colwidth    

Here is a version of code that supports MultiIndex for row and column – it is not pretty but works for me. It expands on @cole-diamond answer:

def _xls_make_columns_wide_enough(dataframe, worksheet, padding=1.1, index=True):
    def get_col_widths(dataframe, padding, index):
        max_width_idx = []
        if index and isinstance(dataframe.index, pd.MultiIndex):
            # Index name lengths
            max_width_idx = [len(v) for v in dataframe.index.names]

            # Index value lengths
            for column, content in enumerate(dataframe.index.levels):
                max_width_idx[column] = max(max_width_idx[column],
                                            max([len(str(v)) for v in content.values]))
        elif index:
            max_width_idx = [
                max([len(str(s))
                     for s in dataframe.index.values] + [len(str(dataframe.index.name))])
            ]

        if isinstance(dataframe.columns, pd.MultiIndex):
            # Take care of columns - headers first.
            max_width_column = [0] * len(dataframe.columns.get_level_values(0))
            for level in range(len(dataframe.columns.levels)):
                values = dataframe.columns.get_level_values(level).values
                max_width_column = [
                    max(v1, len(str(v2))) for v1, v2 in zip(max_width_column, values)
                ]

            # Now content.
            for idx, col in enumerate(dataframe.columns):
                max_width_column[idx] = max(max_width_column[idx],
                                            max([len(str(v)) for v in dataframe[col].values]))

        else:
            max_width_column = [
                max([len(str(s)) for s in dataframe[col].values] + [len(col)])
                for col in dataframe.columns
            ]

        return [round(v * padding) for v in max_width_idx + max_width_column]

    for i, width in enumerate(get_col_widths(dataframe, padding, index)):
        worksheet.set_column(i, i, width)

My version that will go over the one worksheet and autoset the field lengths:

from typing import Optional
from xlsxwriter.worksheet import (
    Worksheet, cell_number_tuple, cell_string_tuple)


def get_column_width(worksheet: Worksheet, column: int) -> Optional[int]:
    """Get the max column width in a `Worksheet` column."""
    strings = getattr(worksheet, '_ts_all_strings', None)
    if strings is None:
        strings = worksheet._ts_all_strings = sorted(
            worksheet.str_table.string_table,
            key=worksheet.str_table.string_table.__getitem__)
    lengths = set()
    for row_id, colums_dict in worksheet.table.items():  # type: int, dict
        data = colums_dict.get(column)
        if not data:
            continue
        if type(data) is cell_string_tuple:
            iter_length = len(strings[data.string])
            if not iter_length:
                continue
            lengths.add(iter_length)
            continue
        if type(data) is cell_number_tuple:
            iter_length = len(str(data.number))
            if not iter_length:
                continue
            lengths.add(iter_length)
    if not lengths:
        return None
    return max(lengths)


def set_column_autowidth(worksheet: Worksheet, column: int):
    """
    Set the width automatically on a column in the `Worksheet`.
    !!! Make sure you run this function AFTER having all cells filled in
    the worksheet!
    """
    maxwidth = get_column_width(worksheet=worksheet, column=column)
    if maxwidth is None:
        return
    worksheet.set_column(first_col=column, last_col=column, width=maxwidth)

just call set_column_autowidth with the column.

Cole Diamond’s answer is awesome. I just updated the subroutine to handle multiindex rows and columns.

def get_col_widths(dataframe):
    # First we find the maximum length of the index columns   
    idx_max = [max([len(str(s)) for s in dataframe.index.get_level_values(idx)] + [len(str(idx))]) for idx in dataframe.index.names]
    # Then, we concatenate this to the max of the lengths of column name and its values for each column, left to right
    return idx_max + [max([len(str(s)) for s in dataframe[col].values] + 
                          [len(str(x)) for x in col] if dataframe.columns.nlevels > 1 else [len(str(col))]) for col in dataframe.columns]

That URL does not specify what the units are for the third argument to set_column.

The column widths are given in multiples of the width of the ‘0’ character in the font Calibri, size 11 (that’s the Excel standard).

I can not find a way to measure the width of the item that I want to insert into the cell.

In order to get a handle on the exact width of a string, you can use tkinter‘s ability to measure string lengths in pixels, depending on the font/size/weight/etc. If you define a font, e.g.

reference_font = tkinter.font.Font(family='Calibri', size=11)

you can afterwards use its measure method to determine string widths in pixels, e.g.

reference_font.measure('This is a string.')

In order to do this for a cell from your Excel table, you need to take its format into account (it contains all the information on the used font). That means, if you wrote something to your table using worksheet.write(row, col, cell_string, format), you can get the used font like this:

used_font = tkinter.font.Font(family     = format.font_name,
                              size       = format.font_size,
                              weight     = ('bold' if format.bold else 'normal'),
                              slant      = ('italic' if format.italic else 'roman'),
                              underline  = format.underline,
                              overstrike = format.font_strikeout)

and afterwards determine the cell width as

cell_width = used_font.measure(cell_string+' ')/reference_font.measure('0')

The whitespace is added to the string to provide some margin. This way the results are actually very close to Excel’s autofit results, so that I assume Excel is doing just that.

For the tkinter magic to work, a tkinter.Tk() instance (a window) has to be open, therefore the full code for a function that returns the required width of a cell would look like this:

import tkinter
import tkinter.font

def get_cell_width(cell_string, format = None):
  root = tkinter.Tk()
  reference_font = tkinter.font.Font(family='Calibri', size=11)
  if format:
    used_font = tkinter.font.Font(family     = format.font_name,
                                  size       = format.font_size,
                                  weight     = ('bold' if format.bold else 'normal'),
                                  slant      = ('italic' if format.italic else 'roman'),
                                  underline  = format.underline,
                                  overstrike = format.font_strikeout)
  else:
    used_font = reference_font
  cell_width = used_font.measure(cell_string+' ')/reference_font.measure('0')
  root.update_idletasks()
  root.destroy()
  return cell_width

Of course you would like to get the root handling and reference font creation out of the function, if it is meant to be executed frequently. Also, it might be faster to use a lookup table format->font for your workbook, so that you do not have to define the used font every single time.

Finally, one could take care of line breaks within the cell string:

pixelwidths = (used_font.measure(part) for part in cell_string.split('n'))
cell_width = (max(pixelwidths) + used_font.measure(' '))/reference_font.measure('0')

Also, if you are using the Excel filter function, the dropdown arrow symbol needs another 18 pixels (at 100% zoom in Excel). And there might be merged cells spanning multiple columns… A lot of room for improvements!

xlsxwriter does not appear to have a method to read back a particular cell. This means I need to keep track of each cell width as I write the cell. It would be better if I could just loop through all the cells, that way a generic routine could be written.

If you do not like to keep track within your own data structure, there are at least three ways to go:

(A) Register a write handler to do the job:
You can register a write handler for all standard types. In the handler function, you simply pass on the write command, but also do the bookkeeping wrt. column widths. This way, you only need to read and set the optimal column width in the end (before closing the workbook).

# add worksheet attribute to store column widths
worksheet.colWidths = [0]*number_of_used_columns
# register write handler
for stdtype in [str, int, float, bool, datetime, timedelta]:
  worksheet.add_write_handler(stdtype, colWidthTracker)


def colWidthTracker(sheet, row, col, value, format):
  # update column width
  sheet.colWidths[col] = max(sheet.colWidths[col], get_cell_width(value, format))
  # forward write command
  if isinstance(value, str):
    if value == '':
      sheet.write_blank(row, col, value, format)
    else:
      sheet.write_string(row, col, value, format)
  elif isinstance(value, int) or isinstance(value, float):
    sheet.write_number(row, col, value, format)
  elif isinstance(value, bool):
    sheet.write_boolean(row, col, value, format)
  elif isinstance(value, datetime) or isinstance(value, timedelta):
    sheet.write_datetime(row, col, value, format)
  else:
    raise TypeError('colWidthTracker cannot handle this type.')


# and in the end...
for col in columns_to_be_autofitted:    
  worksheet.set_column(col, col, worksheet.colWidths[col])

(B) Use karolyi’s answer above to go through the data stored within XlsxWriter’s internal variables. However, this is discouraged by the module’s author, since it might break in future releases.

(C) Follow the recommendation of jmcnamara: Inherit from and override the default worksheet class and add in some autofit code, like this example: xlsxwriter.readthedocs.io/example_inheritance2.html

Some of the solutions given here were too elaborate for the rather simple thing that I was looking for: every column had to be sized so that all its values fits nicely. So I wrote my own solution. It basically iterates over all columns, and for each column it gets all string values (including the column name itself) and then takes the longest string as the maximal width for that column.

# Set the width of the columns to the max. string length in that column
# ~ simulates Excel's "autofit" functionality
for col_idx, colname in enumerate(df.columns):
    max_width = max([len(colname)]+[len(str(s)) for s in df[colname]])
    worksheet.set_column(col_idx, col_idx, max_width+1)  # + 1 to add some padding

Openpyxl easily handles this task. Just install the module and insert the below line of code in your file
# Imorting the necessary modules
try:
from openpyxl.cell import get_column_letter
except ImportError:
from openpyxl.utils import get_column_letter
from openpyxl.utils import column_index_from_string
from openpyxl import load_workbook
import openpyxl
from openpyxl import Workbook

for column_cells in sheet.columns:
    new_column_length = max(len(str(cell.value)) for cell in column_cells)
    new_column_letter = (get_column_letter(column_cells[0].column))
    if new_column_length > 0:
        sheet.column_dimensions[new_column_letter].width = new_column_length*1.23

Update from January 2023.

XlsxWriter 3.0.6+ now supports a autofit() worksheet method:

from xlsxwriter.workbook import Workbook

workbook = Workbook('autofit.xlsx')
worksheet = workbook.add_worksheet()

# Write some worksheet data to demonstrate autofitting.
worksheet.write(0, 0, "Foo")
worksheet.write(1, 0, "Food")
worksheet.write(2, 0, "Foody")
worksheet.write(3, 0, "Froody")

worksheet.write(0, 1, 12345)
worksheet.write(1, 1, 12345678)
worksheet.write(2, 1, 12345)

worksheet.write(0, 2, "Some longer text")

worksheet.write(0, 3, "http://ww.google.com")
worksheet.write(1, 3, "https://github.com")

# Autofit the worksheet.
worksheet.autofit()

workbook.close()

Output:

Or using Pandas:

import pandas as pd

# Create a Pandas dataframe from some data.
df = pd.DataFrame({
    'Country':    ['China',    'India',    'United States', 'Indonesia'],
    'Population': [1404338840, 1366938189, 330267887,       269603400],
    'Rank':       [1,          2,          3,               4]})

# Order the columns if necessary.
df = df[['Rank', 'Country', 'Population']]

# Create a Pandas Excel writer using XlsxWriter as the engine.
writer = pd.ExcelWriter('pandas_autofit.xlsx', engine='xlsxwriter')
df.to_excel(writer, sheet_name='Sheet1', index=False)

# Get the xlsxwriter workbook and worksheet objects.
workbook = writer.book
worksheet = writer.sheets['Sheet1']

worksheet.autofit()

# Close the Pandas Excel writer and output the Excel file.
writer.close()

Output: