[Tutor] Is there a simpler way to remove from a set?

[Alan Gauld]

On 07/05/2021 13:04, Leam Hall wrote:

Hi Leam,

What I asked for was details of how "Python complained"
when you tried to do it without building 2 sets. It still
seems like you should be able to filter the elements in
a single pass...

However,

> def build_set_from_file(file):
>    my_set = set()
>    if Path(file).is_file():
>      readfile = open(file, 'r')
>      for line in readfile.readlines():

Files are iterable, just use

for line in open(file):

No need for readlines()

>        line = line.strip()
>        my_set.add(line)
>    return my_set

And you could use a generator expression:

if Path(file).is_file():
   return set(line.strip() for line in open(file))


> def build_dir_set(dirs):
>    dir_set = set()
>    for item in dirs:
>      path    = Path(item)
>      parent  = str(path.parent)
>      dir_set.add(parent)
>    return dir_set

Again, you could use a generator expression
but its getting a bit messier here.

return set(str(Path(item).parent()) for item in dirs)


-- 
Alan G
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