[Tutor] differences between map and partial?

[Danny Yoo]

On Tue, Sep 27, 2016 at 2:23 AM, source liu <sourceonly at gmail.com> wrote:
> Hi, List
>
> the test code as attached


Unfortunately, it didn't attach.  If you can inline the content of the
test code, that would be helpful.


>     this one works >>>>print p.map(partial(file_op,lineop=unity),input)
>     this one doesn't work >>>>print p.map(lambda x:file_op(x,unity), input)


I don't know what the function signature of file_op is.  This is an
important detail!



I would expect:

    p.map(partial(file_op,lineop=unity),input)

and:

    p.map(lambda x:file_op(x,lineop=unity), input)

to be functionality equivalent.



However, I do not know, without seeing file_op, whether:

    p.map(lambda x:file_op(x, lineop=unity), input)

versus:

    p.map(lambda x:file_op(x, unity), input)

Depending on method signature, this might not be equivalent,
especially if file_op takes in multiple keyword arguments.



Also, I don't know what you mean by "works" vs. "doesn't work": those
are human expressions that are ambiguous enough that I only know
something is wrong, but I don't know what.  :)  Can you be more
specific?  If you see error messages or stack traces, please post
them, as they are additional "signal" that may be helpful in figuring
out what's happening.