NameError: global name 'xrange' is not defined in Python 3

I am getting an error when running a python program:

    Traceback (most recent call last):
      File "C:\Program Files (x86)\Wing IDE 101 4.1\src\debug\tserver\", line 110, in <module>
      File "C:\Program Files (x86)\Wing IDE 101 4.1\src\debug\tserver\", line 27, in __init__
      File "C:\Program Files (x86)\Wing IDE 101 4.1\src\debug\tserver\class\", line 17, in __init__
    builtins.NameError: global name 'xrange' is not defined

The game is from here.

What causes this error?

You are trying to run a Python 2 codebase with Python 3. xrange() was renamed to range() in Python 3.

Run the game with Python 2 instead. Don't try to port it unless you know what you are doing, most likely there will be more problems beyond xrange() vs. range().

For the record, what you are seeing is not a syntax error but a runtime exception instead.

If you do know what your are doing and are actively making a Python 2 codebase compatible with Python 3, you can bridge the code by adding the global name to your module as an alias for range. (Take into account that you may have to update any existing range() use in the Python 2 codebase with list(range(...)) to ensure you still get a list object in Python 3):

        # Python 2
    except NameError:
        # Python 3, xrange is now named range
        xrange = range

    # Python 2 code that uses xrange(...) unchanged, and any
    # range(...) replaced with list(range(...))

or replace all uses of xrange(...) with `range(...) in the codebase and then use a different shim to make the Python 3 syntax compatible with Python 2:

        # Python 2 forward compatibility
        range = xrange
    except NameError:

    # Python 2 code transformed from range(...) -> list(range(...)) and
    # xrange(...) -> range(...).

The latter is preferable for codebases that want to aim to be Python 3 compatible only in the long run, it is easier to then just use Python 3 syntax whenever possible.


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