What is the best way to stop execution of a cell on a Google Datalab notebook?

Question

I would like to halt the execution of a cell executing python commands on a Google Datalab notebook if certain conditions are met.

What is the preferred method to do this that doesn't affect the rest of the notebook?

if x:
   quit()

Will crash the notebook.

Answer 1

One potential solution is to wrap your code in a function and use return to exit early.

def do_work():
  stopExecution = True
  if stopExecution:
     return

  print 'do not print'

do_work()

Another solution is to raise an exception:

stopExecution = True
if stopExecution:
   raise Exception('Done')

print 'do not print'

A better solution is to use the if statement to allow code execution, rather than block it. For example,

if ShouldIContinueWorking():
   doWork()
else:
   print 'Done' # do nothing (preferred) or return from function