Problem involving namedtuple()

Python Help
1

I am trying to port an old Star Trader game to Python3. I have a file of star data in this format:

# nomen,        Idcodes,      spectral,      colour,     abs_mag,      est_mass,     num_obj,        rect3,       notes
Star('Sol', Idcodes('SUN', '--',  'Sol'), 'G2.0 V', Colour(255, 255, 0), 4.85, 1, '1+8P', Rect3(0.0, -0.0, 0.0), '8 planets')
Star('Proxima Centauri', Idcodes('GJ  551 C','49',  'Proxima Centauri'), 'M5.0 V', Colour(192, 51, 0), 15.48, 0.123, '-', Rect3(-0.9717, -0.7437, -0.4407), '"separation 7849"')
Star('alpha Centauri A', Idcodes('GJ  559 A','50',  'alpha Centauri A'), 'G2.0 V', Colour(255, 255, 0), 4.38, 1.14, '3', Rect3(-1.0023, -0.83809, 0.28984), 'none')
Star('alpha Centauri B', Idcodes('GJ  559 B','51',  'alpha Centauri B'), 'K0 V', Colour(255, 153, 0), 5.71, 0.92, '-', Rect3(-1.0021, -0.83783, 0.29098), 'orbit 18" ')

and my setup_cosmos() function is supposed to read this, unpack the data to add game-specific world stuff (like real exoplanet data!), and create stars, a sequence of star objects.
However, the read loop fails on the first iteration; apparently, there are too many values to unpack.

# ...
How many stars to begin with? 15
How long is the game in years? 5
How many tonnes of cargo can a ship carry? 25
# Now we are in setup_cosmos()
# These two lines are my debugging probes
line #0: Star('Sol', Idcodes('SUN', '--',  'Sol'), 'G2.0 V', Colour(255, 255, 0), 4.85, 1, '1+8P', Rect3(0.0, -0.0, 0.0), '8 planets')
  
star: Star('Sol', Idcodes('SUN', '--',  'Sol'), 'G2.0 V', Colour(255, 255, 0), 4.85, 1, '1+8P', Rect3(0.0, -0.0, 0.0), '8 planets')

# And here is the output on failure:
Traceback (most recent call last):
  File# "E:\Binaries\Python311\Scripts\startraders\startrader_new.py", line 1523, in <module>
    trader_setup(ST)
  File "E:\Binaries\Python311\Scripts\startraders\startrader_new.py", line 683, in trader_setup
    setup_cosmos(num_stars, _starfile)
  File "E:\Binaries\Python311\Scripts\startraders\startrader_new.py", line 594, in setup_cosmos
    nomen, idcodes, spectral, colour, abs_mag, est_mass, num_obj, rect3, note = star
ValueError: too many values to unpack (expected 9)
# But there seem to be 9 items in the unpacking tuple.
# So I played around in the debugger and found I could do fairly similar  
# things with other namedtuples in the program:
d = Datei(270, 2185)
a, b = d
a
270
b
2185
# Even successfully run the line which failed:
star = Star('Sol', Idcodes('SUN', '--', 'Sol'), 'G2.0 V', Colour(255, 255, 0), 4.85, 1, '1+8P', Rect3(0.0, -0.0, 0.0), '8 planets')
nomen, idcodes, spectral, colour, abs_mag, est_mass, num_obj, rect3, note = star
nomen
'Sol'
idcodes
Idcodes(GJ='SUN', LHS='--', other='Sol')
note
'8 planets'
est_mass
1

So I am at a loss to understand why Python3 won’t process my star-data file when I can do the same thing manually. What am I doing wrong?

2

Can you provide a full self-contained script that displays the error messages when executed? It’s a bit hard to dig through your mix of code and error messages to figure out what the executed stuff is.

Are you sure star is actually an instance of your namedtuple and not a string?

3

It would be difficult to say exactly what’s going on without seeing the actual code that failed. It seems that you have a file several hundred lines long that isn’t shown here, that does something that causes the problem. In particular;

Well, most likely it doesn’t do all of those things correctly. But we can’t see it here, so who knows.

But at a wild guess: when you read the data from a file, you are just… reading it, so you don’t actually get a Star object. You get a string which you read as a line from the file, where the first character is S, the next is t and so on. Of course that will have a lot more than the expected 9 elements.