Using a Python Dictionary

Data can be passed to the model create_instance() method through a series of nested native Python dictionaries. The structure begins with a dictionary of namespaces, with the only required entry being the None namespace. Each namespace contains a dictionary that maps component names to dictionaries of component values. For scalar components, the required data dictionary maps the implicit index None to the desired value:

>>> import pyomo.environ as pyo
>>> m = pyo.AbstractModel()
>>> m.I = pyo.Set()
>>> m.p = pyo.Param()
>>> m.q = pyo.Param(m.I)
>>> m.r = pyo.Param(m.I, m.I, default=0)
>>> data = {None: {
...     'I': {None: [1,2,3]},
...     'p': {None: 100},
...     'q': {1: 10, 2:20, 3:30},
...     'r': {(1,1): 110, (1,2): 120, (2,3): 230},
... }}
>>> i = m.create_instance(data)
>>> i.pprint()
1 Set Declarations
    I : Size=1, Index=None, Ordered=Insertion
        Key  : Dimen : Domain : Size : Members
        None :     1 :    Any :    3 : {1, 2, 3}

3 Param Declarations
    p : Size=1, Index=None, Domain=Any, Default=None, Mutable=False
        Key  : Value
        None :   100
    q : Size=3, Index=I, Domain=Any, Default=None, Mutable=False
        Key : Value
          1 :    10
          2 :    20
          3 :    30
    r : Size=9, Index=I*I, Domain=Any, Default=0, Mutable=False
        Key    : Value
        (1, 1) :   110
        (1, 2) :   120
        (2, 3) :   230

4 Declarations: I p q r