cpython/Demo/classes/Dbm.py

67 lines
1.2 KiB
Python
Executable File

# A wrapper around the (optional) built-in class dbm, supporting keys
# and values of almost any type instead of just string.
# (Actually, this works only for keys and values that can be read back
# correctly after being converted to a string.)
class Dbm:
def __init__(self, filename, mode, perm):
import dbm
self.db = dbm.open(filename, mode, perm)
def __repr__(self):
s = ''
for key in self.keys():
t = `key` + ': ' + `self[key]`
if s: t = ', ' + t
s = s + t
return '{' + s + '}'
def __len__(self):
return len(self.db)
def __getitem__(self, key):
return eval(self.db[`key`])
def __setitem__(self, key, value):
self.db[`key`] = `value`
def __delitem__(self, key):
del self.db[`key`]
def keys(self):
res = []
for key in self.db.keys():
res.append(eval(key))
return res
def has_key(self, key):
return self.db.has_key(`key`)
def test():
d = Dbm('@dbm', 'rw', 0600)
print d
while 1:
try:
key = input('key: ')
if d.has_key(key):
value = d[key]
print 'currently:', value
value = input('value: ')
if value == None:
del d[key]
else:
d[key] = value
except KeyboardInterrupt:
print ''
print d
except EOFError:
print '[eof]'
break
print d
test()