To see the value of a variable or expression, simply type the variable name
or the expression at the Python prompt, and press Enter. For
example,
>>> myName = 'Einstein'
>>> myName
'Einstein'
>>> 3.0 / 4.0
0.75
>>> x = 3.0 / 4.0
>>> x
0.75
Python creates a variable when you assign a value to it. Python provides
several forms of the assignment statement; for example,
>>> myName = 'Einstein'
>>> myName, yourName = 'Einstein', 'Newton'
>>> myName = yourName = 'Einstein'
The second line assigns the string 'Einstein'
to the variable myName and assigns the string
'Newton' to the variable
yourName. The third line assigns the string
'Einstein' to both
myName and
yourName.
The following naming rules apply:
-
Variable names must start with a letter or an underscore character and
can contain any number of letters, digits, or underscores.
load_3 and
_frictionStep are legal variable names;
3load, load_3$,
and $frictionStep are not legal names. There is
no limit on the length of a variable name.
-
Some words are reserved and cannot be used to name a variable; for
example, print,
while, return,
and class.
-
Python is case sensitive. A variable named
Load is different from a variable named
load.
When you assign a variable in a Python program, the variable refers to a
Python object, but the variable is not an object itself. For example, the
expression numSpokes=3 creates a variable that
refers to an integer object; however,
numSpokes is not an object. You can change the
object to which a variable refers. numSpokes
can refer to a real number on one line, an integer on the next line, and a
viewport on the next line.
The first example script in
Creating a part
created a model using the following statement:
myModel = mdb.Model(name='Model A')
The constructor mdb.Model(name='Model A')
creates an instance of a model, and this instance is a Python object. The
object created is mdb.models['Model A'], and
the variable myModel refers to this object.
An object always has a type. In our example the type of
mdb.models['Model A'] is
Model. An object's type cannot be changed. The
type defines the data encapsulated by an object—its members—and the functions
that can manipulate those data—its methods. Unlike most programming languages,
you do not need to declare the type of a variable before you use it. Python
determines the type when the assignment statement is executed. The
Abaqus Scripting Interface
uses the term object to refer to a specific
Abaqus
type as well as to an instance of that type; for example, a
Model object refers to a
Model type and to an instance of a
Model type.