[Tutor] a quick Q: what does the "collapse" mean?

[Steven D'Aprano]

lina wrote:

> one example:
> 
> def info(object, spacing=10, collapse=1):
>     """Print methods and docs strings.
> 
>     Take modules, class, list, dictionary, or strong."""
>     methodList = [e for e in dir(object) if callable(getattr(object, e))]
>     processFunc = collapse and (lambda s: " ".join(s.split())) or (lambda s: s)
>     print "\n".join(["%s %s" %
>                     (method.ljust(spacing),
>                     processFunc(str(getattr(object, method).__doc__)))
>                     for method in methodList])


In this example, "collapse" is used as the name of an argument which 
takes a true/false flag. If collapse is true, runs of whitespace is 
collapsed into a single space:

"hello         world" => "hello world"

The above function would be much easier to understand if it was written 
like this:

def info(object, spacing=10, collapse=1):
     """Print methods and docs strings.

     Take modules, class, list, dictionary, or string.
     """
     method_names = []
     doc_strings = []
     for name in dir(object):
         attribute = getattr(object, name)
         if callable(attribute):
             method_names.append(name.ljust(spacing))
             doc_strings.append(str(attribute.__doc__))
     if collapse:
         doc_strings = [" ".join(doc.split()) for doc in doc_strings]
     parts = ["%s %s" % (n, d) for n,d in zip(method_names, doc_strings)]
     print "\n".join(parts)



Much longer, but easier to follow for a beginner.



-- 
Steven