Question

I have a folder containing my books that are in various formats (.pdf, .djvu, .dvi). and they all follow the format:

[Name of the Book] – [Author].[an identifier indicating if it searchable or not].[filetype]

I want to make a list of my books that is of the format (x,y,z,t) where x is the name of the book, y is the author, etc. My problem is that when I do:

for file in os.listdir('/home/username/Books'):

file is a string, thus immutable, so I cannot change it.

Answer 1

Strings are immutable, but that doesn’t mean you can’t create the tuple you need from the string.

Something like this should work:

def file_to_tuple(file):
    title_author, searchable, ext = file.rsplit('.', 2)
    title, author = title_author.rsplit(' - ', 1)
    return (title, author, searchable, ext)

You can then use this in a variety of ways to convert your file list to a list of tuples, here are a couple of options:

book_list = map(file_to_tuple, os.listdir('/home/username/Books'))

book_list = [file_to_tuple(f) for f in os.listdir('/home/username/Books')]

str.rsplit() with the maxsplit param is used so that it will not fail for titles that contain a period or a dash, or authors that contain a period, for example:

>>> file_to_tuple('Narnia - The Silver Chair - C.S. Lewis.1.pdf')
('Narnia - The Silver Chair', 'C.S. Lewis', '1', 'pdf')