implement the rest of the dictionary interface for NpzFile (Trac #1125)

[numpy-gitbot]

Original ticket http://projects.scipy.org/numpy/ticket/1125 on 2009-06-03 by atmention:dwf, assigned to unknown.

The patch attached implements a more complete dictionary interface for NpzFile. That is to say, it provides (in addition to the already present getitem()):

• contains - tests for containment of a key in self.files
• iter - returns an iterator over self.files
• keys() - returns a copy of self.files
• values() - returns a list of all arrays in the NpzFile
• iterkeys() - returns an iterator [really a generator] over all items in self.files
• itervalues() - returns an iterator over all arrays in the NpzFile
• items() - returns a list of (key, value) pair tuples
• iteritems() - returns an iterator over (key, value) pair tuples

This allows the convenient "for fname in mynpzfile" syntax, as well as letting you write code that doesn't care whether its input is an in-memory dictionary or a lazily-loaded NpzFile.

[numpy-gitbot]

Attachment added by atmention:dwf on 2009-06-03: io.py.diff

[numpy-gitbot]

atmention:dwf wrote on 2009-06-03

Oops. That should be __contains__, __iter__.

[numpy-gitbot]

atmention:dwf wrote on 2009-06-04

I just noticed the base classes defined in the "collections" module. I wonder if we should be inheriting from collections.Mapping, even though not all of the interface can be efficiently implemented.

[numpy-gitbot]

atmention:pv wrote on 2009-06-04

We can't inherit from collections.Mapping, since Python 2.4 compatibility needs to be maintained.

[numpy-gitbot]

atmention:dwf wrote on 2009-06-04

Good point. In that case, maybe we should inherit from [http://docs.python.org/library/userdict.html#UserDict.DictMixin UserDict.DictMixin], with a comment to the effect that this should eventually be deprecated in favour of collections.Mapping?

[numpy-gitbot]

Milestone changed to Unscheduled by atmention:cournape on 2009-11-27