Re: Resuming a program's execution after correcting error
Sheldon wrote: MRAB wrote: Sheldon wrote: MRAB wrote: Sheldon wrote: Hi. Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. Sorry if this is off-topic here but Dylan (http://www.opendylan.org) is a nice language (I sometimes like even more than python itself) that allows you to continue the work right where the exception was thrown. Henning -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
Henning Hasemann wrote: Sheldon wrote: ... Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. Sorry if this is off-topic here but Dylan (http://www.opendylan.org) is a nice language (I sometimes like even more than python itself) that allows you to continue the work right where the exception was thrown. As I have explained before in this newsgroup, Xerox Parc had that ability (the ability to finish an exception by returning to its source) in their system implementation language, and finally removed the capability when they saw how many bugs were related to its use. --Scott David Daniels [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
MRAB wrote: Sheldon wrote: MRAB wrote: Sheldon wrote: Hi. Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. You could modify the program while you're debugging it so that instead of, say: calculate data write data you have: if saved data exists: load data else: calculate data save data write data The pickle module would be useful here. Matthew I like your idea Matthew but I don't know how to pickle the many variables in one file. Do I need to pickle each and every variable into a seperate file? var1,var2 pickle.dump(var1,f) pickle.dump(var2,f2) Using the 'pickle' module: # To store: f = open(file_path, wb) pickle.dump(var1, f) pickle.dump(var2, f) f.close() # To load f = open(file_path, rb) var1 = pickle.load(f) var2 = pickle.load(f) f.close() A more flexible alternative is to use the 'shelve' module. This behaves like a dict: # To store s = shelve.open(file_path) s[var1] = first s[var2] = [2, 3] s.close() # To load s = shelve.open(file_path) print s[var1] # This prints first print s[var2] # This prints [2, 3] s.close() Hope that helps Matthew Perfect Matthew! Much obliged! /Sheldon -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
MonkeeSage wrote: Georg Brandl wrote: As I said before, this can be done by finding out where the error is raised, what the cause is and by inserting an appropriate try-except-statement in the code. I could be mistaken, but I *think* the OP is asking how to re-enter the stack at the same point as the exception exited from and continue with the execution as if the exception never happened. AFAIK, that isn't possible; however, given that he has a file to work from that indicates a portion of the state at the time of the exception, I think he may be able simulate that kind of functionality by reading in the file on exception and then returning a call to the function where the exception occured with the data from the file. Something like this mockup: def faulty_function(a, b, c=None): if not c: c = 0 try: # modify c, write c to file... # oops hit an exception c += a / b except: # read from the file here # c = ... # and fix the error b += 1 return faulty_function(a, b, c) return c print faulty_function(2, 0) # = 2 Of course, it's probably much better to just fix the code and avoid the exception in the first place. ;) Regards, Jordan Thanks Jordon, I think you understood my problem best. I know now that this is not possible but I would like to create an exception that saves all the current variables when there is an error. I think pickle is the answer but I never got it to work. My program is very large and it is being modified often. Any advice on how to save the variables. /Sheldon -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
MRAB wrote: Sheldon wrote: Hi. Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. You could modify the program while you're debugging it so that instead of, say: calculate data write data you have: if saved data exists: load data else: calculate data save data write data The pickle module would be useful here. Matthew I like your idea Matthew but I don't know how to pickle the many variables in one file. Do I need to pickle each and every variable into a seperate file? var1,var2 pickle.dump(var1,f) pickle.dump(var2,f2) /Sheldon -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
Sheldon wrote: MRAB wrote: Sheldon wrote: Hi. Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. You could modify the program while you're debugging it so that instead of, say: calculate data write data you have: if saved data exists: load data else: calculate data save data write data The pickle module would be useful here. Matthew I like your idea Matthew but I don't know how to pickle the many variables in one file. Do I need to pickle each and every variable into a seperate file? var1,var2 pickle.dump(var1,f) pickle.dump(var2,f2) Using the 'pickle' module: # To store: f = open(file_path, wb) pickle.dump(var1, f) pickle.dump(var2, f) f.close() # To load f = open(file_path, rb) var1 = pickle.load(f) var2 = pickle.load(f) f.close() A more flexible alternative is to use the 'shelve' module. This behaves like a dict: # To store s = shelve.open(file_path) s[var1] = first s[var2] = [2, 3] s.close() # To load s = shelve.open(file_path) print s[var1] # This prints first print s[var2] # This prints [2, 3] s.close() Hope that helps Matthew -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
On 3 Oct 2006 16:58:17 -0700, MRAB [EMAIL PROTECTED] wrote: I like your idea Matthew but I don't know how to pickle the many variables in one file. Do I need to pickle each and every variable into a seperate file? var1,var2 pickle.dump(var1,f) pickle.dump(var2,f2) Using the 'pickle' module: # To store: f = open(file_path, wb) pickle.dump(var1, f) pickle.dump(var2, f) f.close() # To load f = open(file_path, rb) var1 = pickle.load(f) var2 = pickle.load(f) f.close() A more flexible alternative is to use the 'shelve' module. This behaves like a dict: # To store s = shelve.open(file_path) s[var1] = first s[var2] = [2, 3] s.close() # To load s = shelve.open(file_path) print s[var1] # This prints first print s[var2] # This prints [2, 3] s.close() As long as we're on the subject of data serialization, I should like to bring up PyYaml. YAML is a portable format for storing data of all kinds; it became popular via Ruby I think, but there are implementations for many other languages. If you stick to storing simple stuff like lists, strings, and dictionaries, you can use your YAML data almost anywhere, but PyYaml even supports reifying things like lambdas. -- http://mail.python.org/mailman/listinfo/python-list
Resuming a program's execution after correcting error
Hi. Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. Sincerely, Sheldon -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
Sheldon wrote: Hi. Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. As I said before, this can be done by finding out where the error is raised, what the cause is and by inserting an appropriate try-except-statement in the code. There's no way to do that without modifying the code, if the program itself doesn't offer such an option. Georg -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
Sheldon wrote:
Does anyone know if one can resume a python script at the error point
after the error is corrected?
I have a large program that take forever if I have to restart from
scratch everytime. The error was the data writing a file so it seemed
such a waste if all the data was lost and must be recalculated again.
May be you could put some parameter to your main loop:
start_point=begin
if start_point==begin: output=open('outputfile', 'w')
else : output=open('outputfile', 'a')
while start_point = case = end_point:
try:
do_complex_computation(case)
except Exception:
print case
break
If you get an error you repair the program and set
start_point=case
and go on with the program.
Tuomas
--
http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
Sheldon wrote: Hi. Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. Afaik, the best you can do is run the script with python -i, which will give you an interactive prompt from which you have access to the module-level variables. Or even better, test your script with small data sets, and do the real calculations only after you've fixed any obvious bugs. -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
I don't know how much help this is going to be, but you could store values in a temporary file on the hard disk and write checkpoints to read in the data and begin from a point somewhere in the middle of the script. Sheldon wrote: Hi. Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. Sincerely, Sheldon -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
Georg Brandl wrote: As I said before, this can be done by finding out where the error is raised, what the cause is and by inserting an appropriate try-except-statement in the code. I could be mistaken, but I *think* the OP is asking how to re-enter the stack at the same point as the exception exited from and continue with the execution as if the exception never happened. AFAIK, that isn't possible; however, given that he has a file to work from that indicates a portion of the state at the time of the exception, I think he may be able simulate that kind of functionality by reading in the file on exception and then returning a call to the function where the exception occured with the data from the file. Something like this mockup: def faulty_function(a, b, c=None): if not c: c = 0 try: # modify c, write c to file... # oops hit an exception c += a / b except: # read from the file here # c = ... # and fix the error b += 1 return faulty_function(a, b, c) return c print faulty_function(2, 0) # = 2 Of course, it's probably much better to just fix the code and avoid the exception in the first place. ;) Regards, Jordan -- http://mail.python.org/mailman/listinfo/python-list
Re: Resuming a program's execution after correcting error
Sheldon wrote: Hi. Does anyone know if one can resume a python script at the error point after the error is corrected? I have a large program that take forever if I have to restart from scratch everytime. The error was the data writing a file so it seemed such a waste if all the data was lost and must be recalculated again. You could modify the program while you're debugging it so that instead of, say: calculate data write data you have: if saved data exists: load data else: calculate data save data write data The pickle module would be useful here. Matthew -- http://mail.python.org/mailman/listinfo/python-list
