cpython/Lib/anydbm.py

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"""Generic interface to all dbm clones.
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Instead of
import dbm
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d = dbm.open(file, 'w', 0666)
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use
import anydbm
d = anydbm.open(file)
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The returned object is a dbhash, gdbm, dbm or dumbdbm object,
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dependent on availability of the modules (tested in this order).
It has the following interface (key and data are strings):
d[key] = data # store data at key (may override data at
# existing key)
data = d[key] # retrieve data at key (raise KeyError if no
# such key)
del d[key] # delete data stored at key (raises KeyError
# if no such key)
flag = d.has_key(key) # true if the key exists
list = d.keys() # return a list of all existing keys (slow!)
Future versions may change the order in which implementations are
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tested for existence, add interfaces to other dbm-like
implementations, and (in the presence of multiple implementations)
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decide which module to use based upon the extension or contents of an
existing database file.
The open function has an optional second argument. This can be set to
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'r' to open the database for reading only. The default is 'r', like
the dbm default.
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"""
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_names = ['dbhash', 'gdbm', 'dbm', 'dumbdbm']
for _name in _names:
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try:
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exec "import %s; _mod = %s" % (_name, _name)
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except ImportError:
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continue
else:
break
else:
raise ImportError, "no dbm clone found; tried %s" % _names
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error = _mod.error
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def open(file, flag = 'r', mode = 0666):
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return _mod.open(file, flag, mode)