TypeError: unsupported operand type(s) for -: 'int' and 'NoneType'

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Laynufar Silsilia

June 06, 2024 08:12

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Hi,

I get the following error;

TypeError: unsupported operand type(s) for -: 'int' and 'NoneType'

I think this is because of these codes;

m.addConstr(sum(p[n,s] <= 21 for n in range (N) for s in range(S)), "jadwal")
print('constrain 1')

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  Ronald van der Velden

  • Gurobi Staff

  June 06, 2024 08:23

  Hi,

  I suspect the part "<= 21" should move after the for-loops:

  m.addConstr(sum(p[n,s] for n in range (N) for s in range(S)) <= 21, "jadwal")

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  Laynufar Silsilia

  June 06, 2024 08:34

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  If I move the code above, the results appear 

  TypeError: unsupported operand type(s) for -: 'bool' and 'NoneType'

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  Matthias Miltenberger

  • Gurobi Staff

  June 06, 2024 09:02 Edited

  In that case, you should check what the list \(\texttt{p}\) actually contains. It seems, there are incompatible data types present.

  Try this code:

  for n in range(N):
      for s in range(S):
          print(f"{p[n,s]=}, {n=}, {s=}")

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