In the world of data analysis, we often encounter various types of files, and Excel files are one of the most common. However, sometimes, we may come across a peculiar Excel file that refuses to open, no matter what encoding we use. This article will walk you through a real-world example of such a situation and how we can solve it using Python.

Consider this Excel file. When we try to open it using the following Python code, we encounter a UnicodeDecodeError: 'utf-16-le' codec can't decode bytes in position 0-1: unexpected end of data.

import pandas as pd
import xlrd.book
import xlrd
            
wb = xlrd.book.open_workbook_xls('demo.xls')
df = pd.read_excel(wb)
print(df.head())

Upon debugging, we find that characters like b'\xd8' are causing the decoding to fail. The xlrd library provides an encoding_override parameter to specify the encoding format. For instance, we can try using the ‘utf-16’ encoding:

import pandas as pd
import xlrd.book
import xlrd
            
wb = xlrd.book.open_workbook_xls('demo.xls',encoding_override='utf-16')
df = pd.read_excel(wb)
print(df.head())

However, no matter what encoding we use, the error persists. This suggests that there are indeed some encoding errors in the Excel file itself. Since our online environment does not allow us to modify the xlrd library, we resort to a technique called “monkey patching” to solve the problem. Here’s the modified code:

import pandas as pd

def my_unpack_SST_table(datatab, nstrings):
    try:
        return t(datatab, nstrings)
    except:
        for i in range(len(datatab)):
            datatab[i] = datatab[i].replace(b'\xd8', b'\x00')
            datatab[i] = datatab[i].replace(b'\xdf', b'\x00')
            datatab[i] = datatab[i].replace(b'\xdc', b'\x00')
            datatab[i] = datatab[i].replace(b'\xdd', b'\x00')
            datatab[i] = datatab[i].replace(b'\xde', b'\x00')
 
        return t(datatab, nstrings)


import xlrd.book
import xlrd
t = xlrd.book.unpack_SST_table
xlrd.book.unpack_SST_table = my_unpack_SST_table
            
wb = xlrd.book.open_workbook_xls('demo.xls')
df = pd.read_excel(wb)
print(df.head())

With this, we can successfully read the contents of the problematic Excel file. This example illustrates how we can use Python to tackle encoding issues in Excel files, which is a common problem in data analysis. It’s like using a special key to unlock a stubborn door. With the right tools and techniques, we can overcome such challenges and continue our journey in the exciting world of data.