Error with file name handling in python

Question

Minimal working example that shows this error:

from os import listdir, getcwd
from os.path import isfile, join, realpath, dirname
import csv

def gd(mypath, myfile):
    # Obtain the number of columns in the data file
    with open(myfile) as f:
        reader = csv.reader(f, delimiter=' ', skipinitialspace=True)
        for i in range(20):
            row_20 = next(reader)
        # Save number of clumns in 'num_cols'.
        num_cols = len(row_20)
        return num_cols

mypath = realpath(join(getcwd(), dirname(__file__)))

# Iterate through all files. Stores name of file in 'myfile'.
for myfile in listdir(mypath):

    if isfile(join(mypath,myfile)) and (myfile.endswith('.dat')):
        num_cols = gd(mypath, myfile)

print(num_cols)

I have a single file called 'data.dat' in that folder and python returns the error:

----> 9     with open(myfile) as f:
....
IOError: [Errno 2] No existe el archivo o el directorio: u'data.dat'

Which translates to No file or directory: u'data.dat'.

Why is that u being added at the beginning of the file name and how do I get the code to correctly parse the file name?

thats just in the representation ... it means it is a unicode string ... the u is not actually in the string and certainly is not your problem — Joran Beasley
– Joran Beasley, Commented Jun 5, 2013 at 17:57

Otto Allmendinger · Accepted Answer · 2013-06-05 17:56:24Z

6

The u just indicates that it is a unicode string and is not relevant to the problem.

The file isn't found because you aren't adding the mypath in front of the filename - try with open(join(mypath, myfile)) as f:

answered Jun 5, 2013 at 17:56

Otto Allmendinger

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1 Comment

Gabriel Over a year ago

Thank you, but how do I fix that?

Geoff Gerrietts · Accepted Answer · 2013-06-05 17:59:25Z

2

Your problem is that myfile is just a filename, not the result of join(mypath,myfile).

answered Jun 5, 2013 at 17:59

Geoff Gerrietts

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