[python] The equivalent of a GOTO in python

I am self teaching myself python 2.7. I have some experience in using BATCH, which has a GOTO statement. How do I do that in python? For example, suppose I want to jump from line 5 to line 18.

I realize there have been previous questions regarding this topic, but I have not found them sufficiently informative or, are too high level in python for my current understanding.

This question is related to python goto

The answer is


Forgive me - I couldn't resist ;-)

def goto(linenum):
    global line
    line = linenum

line = 1
while True:
    if line == 1:
        response = raw_input("yes or no? ")
        if response == "yes":
            goto(2)
        elif response == "no":
            goto(3)
        else:
            goto(100)
    elif line == 2:
        print "Thank you for the yes!"
        goto(20)
    elif line == 3:
        print "Thank you for the no!"
        goto(20)
    elif line == 20:
        break
    elif line == 100:
        print "You're annoying me - answer the question!"
        goto(1)

I entirely agree that goto is poor poor coding, but no one has actually answered the question. There is in fact a goto module for Python (though it was released as an April fool joke and is not recommended to be used, it does work).


answer = None
while True:
    answer = raw_input("Do you like pie?")
    if answer in ("yes", "no"): break
    print "That is not a yes or a no"

Would give you what you want with no goto statement.


There's no goto instruction in the Python programming language. You'll have to write your code in a structured way... But really, why do you want to use a goto? that's been considered harmful for decades, and any program you can think of can be written without using goto.

Of course, there are some cases where an unconditional jump might be useful, but it's never mandatory, there will always exist a semantically equivalent, structured solution that doesn't need goto.


Disclaimer: I have been exposed to a significant amount of F77

The modern equivalent of goto (arguable, only my opinion, etc) is explicit exception handling:

Edited to highlight the code reuse better.

Pretend pseudocode in a fake python-like language with goto:

def myfunc1(x)
    if x == 0:
        goto LABEL1
    return 1/x

def myfunc2(z)
    if z == 0:
        goto LABEL1
    return 1/z

myfunc1(0) 
myfunc2(0)

:LABEL1
print 'Cannot divide by zero'.

Compared to python:

def myfunc1(x):
    return 1/x

def myfunc2(y):
    return 1/y


try:
    myfunc1(0)
    myfunc2(0)
except ZeroDivisionError:
    print 'Cannot divide by zero'

Explicit named exceptions are a significantly better way to deal with non-linear conditional branching.