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Please let me know if I should provide any more information.

I'm trying to connect a pihut controller to a raspberry pi zero using code I found from approxeng. I am running python 3.5. https://approxeng.github.io/approxeng.input/simpleusage.html#connecting-to-a-controller

from approxeng.input.selectbinder import ControllerResource

    while True:
        try:
            with ControllerResource() as joystick:
                print('Found a joystick and connected')
                while joystick.connected:
                    # Do stuff with your joystick here!
                    # ....
                    # ....
            # Joystick disconnected...
            print('Connection to joystick lost')
        except IOError:
            # No joystick found, wait for a bit before trying again
            print('Unable to find any joysticks')
            sleep(1.0)

However, every time I run this code, or some similar code, I get the same error

    File "/usr/local/lib/python3.5/dist-packages/approxeng/input/__init__.py", line 375
    xname = f'{rootname}x'
    ^
    SyntaxError: invalid syntax

Upon inspecting this file (found here https://github.com/ApproxEng/approxeng.input/blob/master/src/python/approxeng/input/init.py), at line 375 I find 

# Look to see whether we've got pairs of lx,ly and / or rx,ry and create corresponding circular axes
        def add_circular_axis(rootname):
            xname = f'{rootname}x'
            yname = f'{rootname}y'
            if xname in self.axes_by_sname and yname in self.axes_by_sname:
                self.axes_by_sname[rootname] = CircularCentredAxis(x=self.axes_by_sname[xname],
                                                                   y=self.axes_by_sname[yname])

I can't edit this file as it's write-protected, and even if I could edit it, I'm not sure what to do. How can I stop getting this error?

Yacine Hannane
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1 Answers1

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I'm the author of this library - f'{something}' is a syntax introduced in Python3.6, it allows for direct variable insertion into strings (including with formatting characters, although I'm not using those here). The library requires Python3.7, so I'm not particularly surprised it doesn't like running under something earlier.

https://realpython.com/python-f-strings/ for some more detail about this feature, it's really nice!

user2776089
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