How to concatenate three excels files xlsx using python?

Question

Hello I would like to concatenate three excels files xlsx using python.

I have tried using openpyxl, but I don't know which function could help me to append three worksheet into one.

Do you have any ideas how to do that ?

Thanks a lot

Answer 1

Here's a pandas-based approach. (It's using openpyxl behind the scenes.)

import pandas as pd

# filenames
excel_names = ["xlsx1.xlsx", "xlsx2.xlsx", "xlsx3.xlsx"]

# read them in
excels = [pd.ExcelFile(name) for name in excel_names]

# turn them into dataframes
frames = [x.parse(x.sheet_names[0], header=None,index_col=None) for x in excels]

# delete the first row for all frames except the first
# i.e. remove the header row -- assumes it's the first
frames[1:] = [df[1:] for df in frames[1:]]

# concatenate them..
combined = pd.concat(frames)

# write it out
combined.to_excel("c.xlsx", header=False, index=False)

Answer 2

I'd use xlrd and xlwt. Assuming you literally just need to append these files (rather than doing any real work on them), I'd do something like: Open up a file to write to with xlwt, and then for each of your other three files, loop over the data and add each row to the output file. To get you started:

import xlwt
import xlrd

wkbk = xlwt.Workbook()
outsheet = wkbk.add_sheet('Sheet1')

xlsfiles = [r'C:\foo.xlsx', r'C:\bar.xlsx', r'C:\baz.xlsx']

outrow_idx = 0
for f in xlsfiles:
    # This is all untested; essentially just pseudocode for concept!
    insheet = xlrd.open_workbook(f).sheets()[0]
    for row_idx in xrange(insheet.nrows):
        for col_idx in xrange(insheet.ncols):
            outsheet.write(outrow_idx, col_idx, 
                           insheet.cell_value(row_idx, col_idx))
        outrow_idx += 1
wkbk.save(r'C:\combined.xls')

If your files all have a header line, you probably don't want to repeat that, so you could modify the code above to look more like this:

firstfile = True # Is this the first sheet?
for f in xlsfiles:
    insheet = xlrd.open_workbook(f).sheets()[0]
    for row_idx in xrange(0 if firstfile else 1, insheet.nrows):
        pass # processing; etc
    firstfile = False # We're done with the first sheet.

Answer 3

When I combine excel files (mydata1.xlsx, mydata2.xlsx, mydata3.xlsx) for data analysis, here is what I do:

import pandas as pd
import numpy as np
import glob

all_data = pd.DataFrame()
for f in glob.glob('myfolder/mydata*.xlsx'):
   df = pd.read_excel(f)
   all_data = all_data.append(df, ignore_index=True)

Then, when I want to save it as one file:

writer = pd.ExcelWriter('mycollected_data.xlsx', engine='xlsxwriter')
all_data.to_excel(writer, sheet_name='Sheet1')
writer.save()

Answer 4

Solution with openpyxl only (without a bunch of other dependencies).

This script should take care of merging together an arbitrary number of xlsx documents, whether they have one or multiple sheets. It will preserve the formatting.

There's a function to copy sheets in openpyxl, but it is only from/to the same file. There's also a function insert_rows somewhere, but by itself it won't insert any rows. So I'm afraid we are left to deal (tediously) with one cell at a time.

As much as I dislike using for loops and would rather use something compact and elegant like list comprehension, I don't see how to do that here as this is a side-effect show.

Credit to this answer on copying between workbooks.

#!/usr/bin/env python3

#USAGE
#mergeXLSX.py <a bunch of .xlsx files> ... output.xlsx
#
#where output.xlsx is the unified file

#This works FROM/TO the xlsx format. Libreoffice might help to convert from xls.
#localc --headless  --convert-to xlsx somefile.xls

import sys
from copy import copy

from openpyxl import load_workbook,Workbook

def createNewWorkbook(manyWb):
    for wb in manyWb:
        for sheetName in wb.sheetnames:
            o = theOne.create_sheet(sheetName)
            safeTitle = o.title
            copySheet(wb[sheetName],theOne[safeTitle])

def copySheet(sourceSheet,newSheet):
    for row in sourceSheet.rows:
        for cell in row:
            newCell = newSheet.cell(row=cell.row, column=cell.col_idx,
                    value= cell.value)
            if cell.has_style:
                newCell.font = copy(cell.font)
                newCell.border = copy(cell.border)
                newCell.fill = copy(cell.fill)
                newCell.number_format = copy(cell.number_format)
                newCell.protection = copy(cell.protection)
                newCell.alignment = copy(cell.alignment)

filesInput = sys.argv[1:]
theOneFile = filesInput.pop(-1)
myfriends = [ load_workbook(f) for f in filesInput ]

#try this if you are bored
#myfriends = [ openpyxl.load_workbook(f) for k in range(200) for f in filesInput ]

theOne = Workbook()
del theOne['Sheet'] #We want our new book to be empty. Thanks.
createNewWorkbook(myfriends)
theOne.save(theOneFile)

Tested with openpyxl 2.5.4, python 3.4.

Answer 5

You can simply use pandas and os library to do this.

import pandas as pd
import os
#create an empty dataframe which will have all the combined data
mergedData = pd.DataFrame()
for files in os.listdir():
    #make sure you are only reading excel files
    if files.endswith('.xlsx'):
        data = pd.read_excel(files, index_col=None)
        mergedData = mergedData.append(data)
        #move the files to other folder so that it does not process multiple times
        os.rename(files, 'path to some other folder')

mergedData DF will have all the combined data which you can export in a separate excel or csv file. Same code will work with csv files as well. just replace it in the IF condition

Answer 6

Just to add to p_barill's answer, if you have custom column widths that you need to copy, you can add the following to the bottom of copySheet:

        for col in sourceSheet.column_dimensions:
            newSheet.column_dimensions[col] = sourceSheet.column_dimensions[col]

I would just post this in a comment on his or her answer but my reputation isn't high enough.