Is there a way to auto-adjust Excel column widths with pandas.ExcelWriter?

Question

I am being asked to generate some Excel reports. I am currently using pandas quite heavily for my data, so naturally I would like to use the pandas.ExcelWriter method to generate these reports. However the fixed column widths are a problem.

The code I have so far is simple enough. Say I have a dataframe called 'df':

writer = pd.ExcelWriter(excel_file_path)
df.to_excel(writer, sheet_name="Summary")

I was looking over the pandas code, and I don't really see any options to set column widths. Is there a trick out there in the universe to make it such that the columns auto-adjust to the data? Or is there something I can do after the fact to the xlsx file to adjust the column widths?

(I am using the OpenPyXL library, and generating .xlsx files - if that makes any difference.)

Thank you.

Answer 1

Inspired by user6178746's answer, I have the following:

# Given a dict of dataframes, for example:
# dfs = {'gadgets': df_gadgets, 'widgets': df_widgets}

writer = pd.ExcelWriter(filename, engine='xlsxwriter')
for sheetname, df in dfs.items():  # loop through `dict` of dataframes
    df.to_excel(writer, sheet_name=sheetname)  # send df to writer
    worksheet = writer.sheets[sheetname]  # pull worksheet object
    for idx, col in enumerate(df):  # loop through all columns
        series = df[col]
        max_len = max((
            series.astype(str).map(len).max(),  # len of largest item
            len(str(series.name))  # len of column name/header
            )) + 1  # adding a little extra space
        worksheet.set_column(idx, idx, max_len)  # set column width
writer.save()

Answer 2

There is probably no automatic way to do it right now, but as you use openpyxl, the following line (adapted from another answer by user Bufke on how to do in manually) allows you to specify a sane value (in character widths):

writer.sheets['Summary'].column_dimensions['A'].width = 15

Answer 3

I'm posting this because I just ran into the same issue and found that the official documentation for Xlsxwriter and pandas still have this functionality listed as unsupported. I hacked together a solution that solved the issue i was having. I basically just iterate through each column and use worksheet.set_column to set the column width == the max length of the contents of that column.

One important note, however. This solution does not fit the column headers, simply the column values. That should be an easy change though if you need to fit the headers instead. Hope this helps someone :)

import pandas as pd
import sqlalchemy as sa
import urllib


read_server = 'serverName'
read_database = 'databaseName'

read_params = urllib.quote_plus("DRIVER={SQL Server};SERVER="+read_server+";DATABASE="+read_database+";TRUSTED_CONNECTION=Yes")
read_engine = sa.create_engine("mssql+pyodbc:///?odbc_connect=%s" % read_params)

#Output some SQL Server data into a dataframe
my_sql_query = """ SELECT * FROM dbo.my_table """
my_dataframe = pd.read_sql_query(my_sql_query,con=read_engine)

#Set destination directory to save excel.
xlsFilepath = r'H:\my_project' + "\\" + 'my_file_name.xlsx'
writer = pd.ExcelWriter(xlsFilepath, engine='xlsxwriter')

#Write excel to file using pandas to_excel
my_dataframe.to_excel(writer, startrow = 1, sheet_name='Sheet1', index=False)

#Indicate workbook and worksheet for formatting
workbook = writer.book
worksheet = writer.sheets['Sheet1']

#Iterate through each column and set the width == the max length in that column. A padding length of 2 is also added.
for i, col in enumerate(my_dataframe.columns):
    # find length of column i
    column_len = my_dataframe[col].astype(str).str.len().max()
    # Setting the length if the column header is larger
    # than the max column value length
    column_len = max(column_len, len(col)) + 2
    # set the column length
    worksheet.set_column(i, i, column_len)
writer.save()

Answer 4

There is a nice package that I started to use recently called StyleFrame.

it gets DataFrame and lets you to style it very easily...

by default the columns width is auto-adjusting.

for example:

from StyleFrame import StyleFrame
import pandas as pd

df = pd.DataFrame({'aaaaaaaaaaa': [1, 2, 3], 
                   'bbbbbbbbb': [1, 1, 1],
                   'ccccccccccc': [2, 3, 4]})
excel_writer = StyleFrame.ExcelWriter('example.xlsx')
sf = StyleFrame(df)
sf.to_excel(excel_writer=excel_writer, row_to_add_filters=0,
            columns_and_rows_to_freeze='B2')
excel_writer.save()

you can also change the columns width:

sf.set_column_width(columns=['aaaaaaaaaaa', 'bbbbbbbbb'],
                    width=35.3)

UPDATE

In version 1.4 best_fit argument was added to StyleFrame.to_excel. See the documentation.

Answer 5

By using pandas and xlsxwriter you can do your task, below code will perfectly work in Python 3.x. For more details on working with XlsxWriter with pandas this link might be useful https://xlsxwriter.readthedocs.io/working_with_pandas.html

import pandas as pd
writer = pd.ExcelWriter(excel_file_path, engine='xlsxwriter')
df.to_excel(writer, sheet_name="Summary")
workbook = writer.book
worksheet = writer.sheets["Summary"]
#set the column width as per your requirement
worksheet.set_column('A:A', 25)
writer.save()

Answer 6

Easiest solution is to specify width of column in set_column method.

    for worksheet in writer.sheets.values():
        worksheet.set_column(0,last_column_value, required_width_constant)

Answer 7

Combining the other answers and comments and also supporting multi-indices:

def autosize_excel_columns(worksheet, df):
  autosize_excel_columns_df(worksheet, df.index.to_frame())
  autosize_excel_columns_df(worksheet, df, offset=df.index.nlevels)

def autosize_excel_columns_df(worksheet, df, offset=0):
  for idx, col in enumerate(df):
    series = df[col]
    max_len = max((
      series.astype(str).map(len).max(),
      len(str(series.name))
    )) + 1
    worksheet.set_column(idx+offset, idx+offset, max_len)

sheetname=...
df.to_excel(writer, sheet_name=sheetname, freeze_panes=(df.columns.nlevels, df.index.nlevels))
worksheet = writer.sheets[sheetname]
autosize_excel_columns(worksheet, df)
writer.save()

Answer 8

import re
import openpyxl
..
for col in _ws.columns:
    max_lenght = 0
    print(col[0])
    col_name = re.findall('\w\d', str(col[0]))
    col_name = col_name[0]
    col_name = re.findall('\w', str(col_name))[0]
    print(col_name)
    for cell in col:
        try:
            if len(str(cell.value)) > max_lenght:
                max_lenght = len(cell.value)
        except:
            pass
    adjusted_width = (max_lenght+2)
    _ws.column_dimensions[col_name].width = adjusted_width