On 4/29/19 3:26 PM, Terry Reedy wrote:
On 4/29/2019 1:38 PM, Dave wrote:
As apps get more complex we add modules, or Python files, to organize things.  One problem I have is a couple of data classes (list of dictionary objects) in a few modules that are used in a number of the other modules.  For example a list of meter reading dictionaries in one module is used by the user interface module to get the data from the user, a report module to display the data, and a file module to save and retrieve the data to/from file.  All the modules need to use the same instance of the list classes.


There are a number of ways to do this.  One is a module that creates the objects, then import that module into all of the others.  Works well,

You can have one *or more* such modules.  Perhaps you already do.

but may not be the best way to do the job.

In what way do you consider it unsatisfactory.

It is not that I consider it unsatisfactory as much as I'm looking for the best way. I am constantly amazed at the thought that has been given to this language (with the exception of access modifiers - perhaps, and lack of a case statement), and often find that there is a better way of doing everything.



A slight variation is to do this in the main module, but the main module has to be imported into the others.

Avoid import loops unless really necessary.  They often work, but when they don't ... its a pain.

  Since I use the main module as a calling module to load data, start the user interface, and to close things down, it may not be the best place to also create the classes.

Another way to do this is have a line in each module to check the name. If it is the module name, then create the class and then import these modules in all the others.  A tad messy and maybe a little confusing.

Right.



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