diff options
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/library/collections.rst | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst index cff07b9..e886d86 100644 --- a/Doc/library/collections.rst +++ b/Doc/library/collections.rst @@ -550,16 +550,6 @@ by the :mod:`csv` or :mod:`sqlite3` modules:: for emp in map(EmployeeRecord._make, cursor.fetchall()): print(emp.name, emp.title) -Named tuples can also be used to generate enumerated constants: - -.. testcode:: - - def enum(*names): - return namedtuple('Enum', ' '.join(names))(*range(len(names))) - - Status = enum('open', 'pending', 'closed') - assert (0, 1, 2) == (Status.open, Status.pending, Status.closed) - In addition to the methods inherited from tuples, named tuples support three additional methods and one attribute. To prevent conflicts with field names, the method and attribute names start with an underscore. @@ -655,6 +645,15 @@ customize a prototype instance: >>> default_account = Account('<owner name>', 0.0, 0) >>> johns_account = default_account._replace(owner='John') +Enumerated constants can be implemented with named tuples, but it is simpler +and more efficient to use a simple class declaration: + + >>> Status = namedtuple('Status', 'open pending closed')._make(range(3)) + >>> Status.open, Status.pending, Status.closed + (0, 1, 2) + >>> class Status: + ... open, pending, closed = range(3) + .. rubric:: Footnotes .. [#] For information on the double-star-operator see |