meaning of [ ]

[Peter Otten]

Andrej Viktorovich wrote:

> Hello,
> 
> Trying to understand command:
> [p for p in sys.path]
> 
> It prints array of paths. I suppose p becomes array of strings but what []
> means in this statement?

This is called "list comprehension", and

paths = [p for p in sys.path if "foo" in p]

is roughly equivalent to

paths = []
for p in sys.path:
    if "foo" in p:
        paths.append(p)

Your original example

> [p for p in sys.path]

just copies the items from sys.path into a new list. This is usually done 
with the more concise

list(sys.path)