Error
inshu chauhan
insideshoes at gmail.com
Tue Nov 20 04:06:02 EST 2012
thanx ..I understand the problem now..
On Wed, Nov 14, 2012 at 7:48 PM, MRAB <python at mrabarnett.plus.com> wrote:
> On 2012-11-14 15:18, inshu chauhan wrote:
>
>>
>> for this code m getting this error :
>>
>> CODE :
>> def ComputeClasses(data):
>> radius = .5
>> points = []
>> for cy in xrange(0, data.height):
>> for cx in xrange(0, data.width):
>> if data[cy,cx] != (0.0,0.0,0.0):
>> centre = data[cy, cx]
>> points.append(centre)
>>
>>
>> Look at this line:
>
> change = True
>>
>> It's indented the same as the preceding 'if' statement, which means
> that it's executed even if the body of the 'if' statement wasn't
> executed and it hasn't assigned to 'centre'.
>
> So 'change' has been set to True, the 'while' loop is entered, and
> subsequently an attempt is made to get 'centre', which hasn't been set.
>
>
> while change:
>>
>> for ring_number in xrange(1, 1000):
>> change = False
>> new_indices = GenerateRing(cx, cy, ring_number)
>>
>>
>> for idx in new_indices:
>> point = data[idx[0], idx[1]]
>>
>> if point == (0.0, 0.0, 0.0 ):
>> continue
>> else:
>> dist = distance(centre, point)
>> if dist < radius :
>> print point
>> points.append(point)
>> change = True
>> print change
>>
>>
>> The indentation of this line looks wrong to me:
>
> break
>>
>
But If I change the indentation of break towards inside, its going into
infinite loop.. ???
>
>> It'll affect the 'for cx' loop at the end of its first iteration, every
> time.
>
>
>> ERROR :
>> Traceback (most recent call last):
>> File "Z:\modules\classification2.**py", line 74, in <module>
>> ComputeClasses(data)
>> File "Z:\modules\classification2.**py", line 56, in ComputeClasses
>> dist = distance(centre, point)
>> UnboundLocalError: local variable 'centre' referenced before assignment
>>
>> And i am unable to understand .. WHY ?
>>
>>
> --
> http://mail.python.org/**mailman/listinfo/python-list<http://mail.python.org/mailman/listinfo/python-list>
>
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