• The function takes the directory pathname as argument. The function shouldn't have to qualify this directory in any way (for example, by adding a '../' to the path). If the directory being searched is in a different directory than the current one, the function should be called with that path included -- for example, if 'shakespeare' is in the parent directory, the call should be get_file_sizes('../shakespeare')
• Initialize an empty dictionary to hold the filenames and file sizes
• Use os.listdir() to list the contents of the directory. This function returns a list.
• Next, loop through the list.
• Inside the 'for' loop, you'll first want to skip over 'hidden' files - these are files that start with a period. If the filename starts with a period, use continue to skip to the next item.
• Also inside the 'for' loop, you'll need to join the filename to the directory name to produce a path to the file.
• You'll also want to skip over any files that are not actually files, but directories. I used not os.path.isfile() to ask whether the entry is not a file and not a directory, and continue to jump to the top of the loop and the next filename in the list. (Keep in mind that you can't check .isdir() against the filename, it needs to be filepath so that the os can find the directory you're talking about. Since os.path.isdir() returns True or False, if you check it with only the directory name or file name it will simply look for that in the current directory, not find it, and just return False.)
• Next, you can use os.path.getsize() to get the size of the file.
• Finally, you can add a simple key/value pair to the dictionary: the key should be the filename (not the full path) and the value should be the size of the file.
• There is no need to check to see if the key is in the dict - every filename should be unique, so you can just add the pair without doing any checks on the dict.
• After the 'for' loop is complete, return the dict from the function.

Please let me know your questions!

The program does require a loop within a loop -- the outer loop reads the name of each file in a directory; the inner loop reads each line in each file: Note: this does not need to use a function. The program takes command-line arguments.

# read command-line arguments for directory and search term
# list the files in the directory

# loop through each file in listing of files in directory
  # skip if the filename starts with a '.'
  # skip if the file is actually a directory
  # open the file
  # set a counter to 0
  # loop through each line in the file
    # if the search term is in the line,
      # print the filename, line number, file line

Special Note: if (and only if) you see a UnicodeDecodeError, it may be because you attempted to open a nonstandard file - MacOS files sponteneously appear in directories and I'm not always successful in removing them. Make sure to test the file to see if it starts with a period -- if so please skip it with the continue statement (while inside the os.listdir() loop). (If you don't see a UnicodeDecodeError then you do not need to do this.)
Note that if Python can't find your directory, it may be because the relative path is incorrect. Please see "Filepaths for Locating Files" in Session 3 Slides.

The overall approach contemplated here is to list the files in the directory and store them in a set; wait 5 seconds; then list the files into a set again, and compare the sets. You'll do oldset.difference(newset) to detect file deletions and newset.difference(oldset) to detect file additions. Putting this process into a while(True) loop allows this process to go on indefinitely. Since the while(True) loop has no natural way to break out, the program requires the use of Ctrl-C to exit. The logic of the while(True) loop can be done in different order, perhaps, but here is the logic outline that worked for me:

# test sys.argv to affirm that dir argument has been passed

# list files into set ("old" set)

# start while True: loop

    # sleep 5 seconds
    # list files into set ("new" set)
    # compare sets to see what files have been added
    # compare sets to see what files have been removed
    # report any added or removed files

    # assign "new" set to "old" set variable for next loop
      comparison

Note that if Python can't find your directory, it may be because the relative path is incorrect. Please see "Filepaths for Locating Files" in Session 3 Slides.

Note that if Python can't find your file, it may be because the relative path is incorrect. Please see "Filepaths for Locating Files" in Session 3 Slides.

In the "directory grep" assignment, there are two error conditions that must be anticipated: 1. if the user doesn't enter two arguments at the command line 2. if the user enters a directory that doesn't exist. Both of these error conditions can be detected through 'if' tests. But they can also be trapped as exceptions. For example, what exception would occur if the user had not entered 2 arguments and you attempted to read them from sys.argv? And what exception would occur if the program attempted to read from a non-existent directory? To find out, take out your tests that check to see if you have enough arguments (if you have one). Then run it with not enough arguments - one argument or no argument. Note the exception type that you see, and the line it occurs on. Then wrap that line (and the other line reading from sys.argv) in a try: block, and follow that with an except: block. Inside the except: block print an error message and exit. Do the same thing for a bad directory -- deliberately feed a bad directory to the program, note the exception type and where it occurred, and then wrap that line in a try:.