sys.exit() will do exactly what you want.
import sys
sys.exit("Error message")
import sys
sys.exit()
This will exit with status code 0; if you don't want that, you can pass a different one or a message:
sys.exit(1)
details from the sys module documentation:
sys.exit([arg])Exit from Python. This is implemented by raising the
SystemExitexception, so cleanup actions specified by finally clauses oftrystatements are honored, and it is possible to intercept the exit attempt at an outer level.The optional argument arg can be an integer giving the exit status (defaulting to zero), or another type of object. If it is an integer, zero is considered “successful termination” and any nonzero value is considered “abnormal termination” by shells and the like. Most systems require it to be in the range 0-127, and produce undefined results otherwise. Some systems have a convention for assigning specific meanings to specific exit codes, but these are generally underdeveloped; Unix programs generally use 2 for command line syntax errors and 1 for all other kind of errors. If another type of object is passed, None is equivalent to passing zero, and any other object is printed to
stderrand results in an exit code of 1. In particular,sys.exit("some error message")is a quick way to exit a program when an error occurs.Since
exit()ultimately “only” raises an exception, it will only exit the process when called from the main thread, and the exception is not intercepted.
Note that this is the 'nice' way to exit. @glyphtwistedmatrix below points out that if you want a 'hard exit', you can use os._exit(*errorcode*), though it's likely os-specific to some extent (it might not take an errorcode under windows, for example), and it definitely is less friendly since it doesn't let the interpreter do any cleanup before the process dies. On the other hand, it does kill the entire process, including all running threads, while sys.exit() (as it says in the docs) only exits if called from the main thread, with no other threads running.
A simple way to terminate a Python script early is to use the built-in quit() function. There is no need to import any library, and it is efficient and simple.
Example:
#do stuff
if this == that:
quit()
However, this relies on an implicit import of the site module. Per the docs:
The site module (which is imported automatically during startup, except if the -S command-line option is given) adds several constants to the built-in namespace. They are useful for the interactive interpreter shell and should not be used in programs.
As such, if the -S flag is passed, this may raise a NameError with the message "name 'quit' is not defined".
Terminate code
execution - How to stop/terminate a python script from running? - Stack Overflow
Is there a way to immediately stop a python script with a keystroke?
Debugging a python script with arguments in bash
Hey, how can we end a program without using break, exit or quit functions. Like just using if statement how can I terminate a program?
You can also do it if you use the exit() function in your code. More ideally, you can do sys.exit(). sys.exit() which might terminate Python even if you are running things in parallel through the multiprocessing package.
Note: In order to use the sys.exit(), you must import it: import sys
To stop your program, just press Control + C.