IndexError: list index out of range

[yahyawasim97]

IndexError Traceback (most recent call last)
in
79 list_of_files = [f for f in os.listdir(data_path) if os.path.isfile(os.path.join(data_path, f)) and '_data' in f]
80
---> 81 file_sig = list_of_files[file_idx]
82 file_stim = list_of_files[file_idx].replace('_data','_labels')
83 print( "File Name: ", file_sig, file_stim)