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Is it possible to generate variables from a list ??

Answer 1

+1 A:

The global variables are in a dictionary that you can get by calling the globals() function.

globals()["foo"] = 17
foo  # => 17

But you should probably refactor your code to use objects, and then use setattr() instead.

dkagedal 2010-10-05 22:25:12

Thanks for your answer, it really helps; but what do you mean by: But "you should probably refactor your code to use objects, and then use setattr() instead"???

relima 2010-10-05 22:27:23

I assumed that your code was running at the top level in your Python file. If it was in fact running within a function, you might want to use `locals()` instead (I don't know what you want to do).

dkagedal 2010-10-05 22:30:07

If i was going to create variables named from the matches of a regular express (e.g. if I was on the tail end of a week long drinking binge) I would probably use `locals()`

aaronasterling 2010-10-05 22:31:31

... but this all seems like poor design. Why would you have code that dynamically creates variables? Variables are for you, the programmer, to create, and having the program create them behind your back only leads to confusion. Your program should handle data, and data belongs in data structures, just like the list in your example. If the list is not good enough for your purposes, you should use a better data structure, not spill the data on the floor by setting all kinds of variables. Creating an object and setting attributes in it (using setattr) is one way to do it.

dkagedal 2010-10-05 22:32:04

@dkagedal. `locals()` works at any level. When at top level, `locals() == globals()`

aaronasterling 2010-10-05 22:32:13

what he means is that though setting varialbes through `globals()` can work, it's not guaranteed by the language spec, this could change with a minor version update.

TokenMacGuy 2010-10-05 22:33:15

vr_ctrs.getChild(i+"-GEODE") returns an object with its own properties. I need to be able to set these properties with a dot command. That is why I need to generate the variables.

relima 2010-10-05 22:35:29

But maybe the setattr() will work as well. I ill give it a try.

relima 2010-10-05 22:36:14

No, `globals()`is defined by the library specification. Changing it with a minor version update is not very likely.

dkagedal 2010-10-05 22:36:27

But why not just set a temporary variable? `chld = vr_ctrs.getChild(...) ; chld.foobar`

dkagedal 2010-10-05 22:38:03

If the attribute name ("foobar" in my example) is dynamically chosen, you should use `getattr()` and `setattr()`.

dkagedal 2010-10-05 22:39:08

Thank you very much for your help. I managed to use these functions..

relima 2010-10-06 00:32:00

Answer 2

+4 A:

I would suggest that instead of creating variables, that you capture these entries in a dict, using what you would have used as the variable name for the dict keys. Then you can easily navigate through the parsed data by accessing dict.keys(), and you wont have to sort out your variables from other local or global variables. Also, if you happen to parse something that accidentally collides with a Python keyword (like 'for', for example), then using that as a dict key will still work, while using it as a variable or attribute name is not going to work.

Paul McGuire 2010-10-05 22:47:41

This is awesome. I had forgotten that I could use a dictionary for storing the variables. It worked great, thanks.

relima 2010-10-06 01:57:58

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Is it possible to generate variables from a list ??

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