为什么Python在我认为文件不存在时会认为该文件不存在？

Question

I'm trying to import some files to plot, and all was going well until I moved my program to the directory above where it was before. The relevant piece of code that seems to be problematic is below:

import os
import pandas as pd

path = os.getcwd() + '/spectrum_scan/'
files = os.listdir(path)
dframefiles = pd.DataFrame(files)

up = pd.read_csv(dframefiles.ix[i][0])

If I type directly into the shell os.path.exists(path) it returns True .

The first file in the directory spectrum_scan is foo.csv .

When I type os.path.exists(path + 'foo.csv') it returns True but os.path.isfile('foo.csv') returns False .

Also, asking for files and dframefiles returns everything as it should, but when the code is run I get Exception: File foo.csv does not exist .

Is there something obvious I'm missing?

Answer 1

You are using os.listdir() , which returns filenames without a path. You'll need to add the path to these:

files = [os.path.join(path, f) for f in os.listdir(path)]

otherwise python will try and look for 'foo.csv' in the current directory, and not in the spectrum_scan sub-directory where the files really are located.