Expression

class gamspy.Expression(left: OperableType | ImplicitEquation | None, data: str, right: OperableType | str | None)

Bases: Operable

Expression of two operands and an operation.

Parameters:

left: str | int | float | Parameter | Variable | None

Left operand

data: str

Operation

right: str | int | float | Parameter | Variable | None

Right operand

Attributes:

records

Evaluates the expression and returns the resulting records.

representation

Methods

gamsRepr()	Representation of this Expression in GAMS language.
getDeclaration()	Declaration of the Expression in GAMS
latexRepr()	Representation of this Expression in Latex.
toList()	Convenience method to return the records of the expression as a list.
toValue()	Convenience method to return expression records as a Python float.

Examples

>>> import gamspy as gp
>>> m = gp.Container()
>>> a = gp.Parameter(m, name="a")
>>> b = gp.Parameter(m, name="b")
>>> expression = a * b
>>> expression.gamsRepr()
'(a * b)'

gamsRepr() → str

Representation of this Expression in GAMS language.

Returns:

str

Examples

>>> import gamspy as gp
>>> m = gp.Container()
>>> a = gp.Parameter(m, name="a")
>>> b = gp.Parameter(m, name="b")
>>> expression = a * b
>>> expression.gamsRepr()
'(a * b)'

getDeclaration() → str

Declaration of the Expression in GAMS

Returns:

str

Examples

>>> import gamspy as gp
>>> m = gp.Container()
>>> a = gp.Parameter(m, name="a")
>>> b = gp.Parameter(m, name="b")
>>> expression = a * b
>>> expression.getDeclaration()
'(a * b)'

latexRepr() → str

Representation of this Expression in Latex.

Returns:

str

toList() → list | None

Convenience method to return the records of the expression as a list.

Returns:

list | None

Examples

>>> import numpy as np
>>> import gamspy as gp
>>> m = gp.Container()
>>> i = gp.Set(m, records=range(3))
>>> a = gp.Parameter(m, domain=i, records=np.array([1,2,3]))
>>> b = gp.Parameter(m, domain=i, records=np.array([4,5,6]))
>>> (a + b).toList()
[['0', 5.0], ['1', 7.0], ['2', 9.0]]

toValue() → float | None

Convenience method to return expression records as a Python float. Only possible if there is a single record as a result of the expression evaluation.

Returns:

float | None

Raises:

TypeError

In case the dimension of the expression is not zero.

Examples

>>> import gamspy as gp
>>> m = gp.Container()
>>> a = gp.Parameter(m, records=5)
>>> b = gp.Parameter(m, records=6)
>>> (a + b).toValue()
np.float64(11.0)

property records: pd.DataFrame | None

Evaluates the expression and returns the resulting records.

Returns:

pd.DataFrame | None

Examples

>>> import gamspy as gp
>>> m = gp.Container()
>>> a = gp.Parameter(m, records=5)
>>> b = gp.Parameter(m, records=6)
>>> (a + b).records
   value
0   11.0

property representation: str

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