Hi you can use has_key() to check whether the particular value is in the key set or not.
>>> a = {} >>> a[1] = 22 >>> a[2] = 33 >>> a {1: 22, 2: 33} >>> a.has_key(3) False >>> a.has_key(1) True >>> -raj KraftDiner wrote: > Ok so this is nice.. Just one thing.. When you try to get a value from > a dictionary > and it isn't found in the dictionary things go bad... > > Take this for example: > > class histogram(object): > def __init__(self): > self.histo = {} > > def update(self, point): > if self.histo.get(point) != None: > self.histo[point] = self.histo[point] + 1 > else: > self.histo[point] = 1 > > def get(self, point): > return self.histo[point] > > > hist = histogram() > hist.update((0,0,0)) > hist.update((0,0,1)) > hist.update((0,0,1)) > hist.get((0,0,0)) > hist.get((0,0,1)) > hist.get((0,0,2)) > > spews out this error: > > Traceback (most recent call last): > File "histogram.py", line 21, in ? > hist.get((0,0,2)) > File "histogram.py", line 12, in get > return self.histo[point] > KeyError: (0, 0, 2) -- http://mail.python.org/mailman/listinfo/python-list