Greetings!
Here's my script:
######## start of script
class ScannerCommand:
taskName = ''
scanList = []
def __init__(self):
print "Creating a ScannerCommand object; list has " + \
str(len(self.scanList)) + " objects."
class Scanner:
def Read(self, data):
command = ScannerCommand()
command.scanList.append(data)
return command
class Handler:
def Process(self, dataList):
print "Processing data"
for data in dataList:
print " " + data
print "Finished processing data."
if __name__ == '__main__':
s = Scanner()
count = 0
for data in ["Zero", "One", "Two", "Three"]:
command = s.Read(data)
handler = Handler()
handler.Process(command.scanList)
############## End of script
Here's the result:
########## Start of result
Processing data
Zero
Finished processing data.
Creating a ScannerCommand object; list has 1 objects.
Processing data
Zero
One
Finished processing data.
Creating a ScannerCommand object; list has 2 objects.
Processing data
Zero
One
Two
Finished processing data.
Creating a ScannerCommand object; list has 3 objects.
Processing data
Zero
One
Two
Three
Finished processing data.
################ End of result
I had expected to get "Zero" by itself, then "One" by itself, and so
on.
Why is the ScannerCommand object being created with a scanList that
contains the data that was in the previously created ScannerCommand
object? And what do I have to do to ensure that the code that is run
when I call ScannerCommand() gives me an object with an empty scanList?
I am a C++ developer in a shop that uses some Python as well, and I
just ran across this behavior for the first time. I believe it is due
to the difference between binding a variable to an object, as Python
does, and actually creating the variable, as a similar C++ application
would do.
Thank you very much.
Rob Richardson
RAD-CON, Inc.
Bay Village, OH
--
http://mail.python.org/mailman/listinfo/python-list
