为什么我收到 IndexError: list index out of range 这个函数？

Question

I am trying to concatenate a list of xlsx files. Here is my code:

import pandas as pd
from glob import glob


files = glob('DS*.xlsx')
files_combined = pd.concat((pd.read_excel(x).assign(filename = x) for x in files))

I get

 IndexError: list index out of range

I did a lot of research and it seems that the problem people suspect is that glob returns a blank list. However, when I change my code to

import pandas as pd
from glob import glob

files = glob('RC*.xlsx')
print(files)

I get a list of the files I am looking to concatenate. I have tried changing my code to

  import pandas as pd
  from glob import glob
  import os

  DIR = 'Y:\\files\'
  files = glob(os.path.join(DIR, 'DS*.xlsx'))
  files_combined = pd.concat((pd.read_excel(x).assign(filename = x)
       for x in files))

but I get the same error.

Answer 1

I ran this (basically your original code) successfully:

import os
import pandas as pd
from glob import glob

os.chdir('C:/users/xxxx/')
files = glob('*.xlsx')
files_combined = pd.concat((pd.read_excel(x).assign(filename = x) for x in files))

No errors, so I added this and reran:

print(files_combined)

The result is the concatenation of the 5 xlsx files in my directory.

Then I wanted to test the "no files" option, so I changed my glob statement:

import os
import pandas as pd
from glob import glob

os.chdir('C:/users/xxxx/')
files = glob('*.xlsx1234')
files_combined = pd.concat((pd.read_excel(x).assign(filename = x) for x in files))

Now I get the error "No objects to concatenate". So a blank list will not return the "list index out of range" error either.