# View of Constraints and Decision Variables in Pyomo

I have just attempted to construct my first Pyomo model.

However, I was unable to locate any documentation that shows how to view constraints, decision variables.

As my model is big, I need to see that they are created and indexed correctly from time-to-time before proceeding further.

May I ask if anyone has chanced upon such documentation or have devised any ingenious method to do so within the confines of Python or Pyomo syntax?

Thank you!

• Not too familiar with Pyomo, but wouldn’t model.write(“model.lp”) write your model to an lp file (which is very readable) – Mason Jul 22 '20 at 1:27

After defining your model by putting the following statement in your code (wherever you want before or after solve command) your model with all the objects has been printed:

model.pprint()


If you like to print constraints or variables individually:

model.cons1.pprint()  # For entire ConstraintList
print(model.cons2[i].expr)  # For only one index of ConstraintList
model.write() # To write the model into a file using .nl format


Assuming that model is the model that you defined and cons1 and cons2 are two ConstraintsList in that model.

• Thanks again for your generosity! – Mike Jul 24 '20 at 2:44
• @Mike you are welcome... – Oguz Toragay Jul 24 '20 at 2:47