Python: how to use glob and wildcard to open CDF files

I'm trying to open multiple .cdf files and store them in a dictonary, but when I try to use wildcard within the pycdf.CDF() command, this error is returned: spacepy.pycdf.CDFError: NO_SUCH_CDF: The specified CDF does not exist.

The .cdf files have a set initial name (instrumentfile), a date (20010101) and then a variable section (could be 1, 2, 3, or 4). This means that I can't simply write code such as:

DayCDF = pycdf.CDF('/home/location/instrumentfile'+str(dates)+'.cdf')

I also need to change the names of the variables that the .cdf data is assigned to as well, so I'm trying to import the data into a dictionary (also not sure if this is feasible).

The current code looks like this:

dictDayCDF = {}

for x in range(len(dates)):
    dictDayCDF["DayCDF"+str(x)] = pycdf.CDF('/home/location/instrumentfile'+str(dates[x])+'*.cdf')

and returns the error spacepy.pycdf.CDFError: NO_SUCH_CDF: The specified CDF does not exist.

I have also tried using glob.glob as I have seen this recommended in answers to similar questions but I have not been able to work out how to apply the command to opening .cdf files:

dictDayCDF = {}

for x in range(len(dates)):
    dictDayCDF["DayCDF"+str(x)] = pycdf.CDF(glob.glob('/home/location/instrumentfile'+str(dates[x])+'*.cdf'))

with this error being returned: ValueError: pathname must be string-like

The expected result is a dictionary of .cdf files that can be called with names DayCDF1, DayCDF2, etc that can be imported no matter the end variable section.

Solution

How about starting with the following code skeleton:

import glob

for file_name in glob.glob('./*.cdf'):
    print(file_name)
    #do something else with the file_name

As for the root cause of the error message you're encountering: if you check the documentation of the method you're trying to use, it indicates that

Open or create a CDF file by creating an object of this class. Parameters:

pathname : string
name of the file to open or create

based on that, we can infer that it's expecting a single file name, not a list of file names. When you try to force a list of file names, that is, the result of using glob, it complains as you've observed.