[Tutor] Multiprocessing with many input input parameters

[Cameron Simpson]

On 11Jul2019 15:40, Mike Barnett <mike_barnett at hotmail.com> wrote:
>If you're passing parameters as a list, then you need a "," at the end of the items.  Otherwise if you have something like a string as the only item, the list will be the string.
>
>list_with_one_item = ['item one',]

Actually, this isn't true.

This is a one element list, no trailing coma required:

  [5]

Mike has probably confused this with tuples. Because tuples are 
delineated with parentheses, there is ambiguity between a tuple's 
parentheses and normal "group these terms together" parentheses.

So:

  x = 5 + 4 * (9 + 7)

Here we just have parentheses causing the assignment "9 + 7" to occur 
before the multiplication by 4. And this is also legal:

  x = 5 + 4 * (9)

where the parentheses don't add anything special in terma of behaviour.

Here is a 2 element tuple:

  (9, 7)

How does one write a one element tuple? Like this:

  (9,)

Here the trailing comma is _required_ to syntacticly indicate that we 
intend a 1 element tuple instead of a plain "9 in parentheses") as in 
the earlier assignment statement.

I'm not sure any of this is relevant to Sydney's question though.

Cheers,
Cameron Simpson <cs at cskk.id.au>