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.. function:: name_declared
Syntax:
``type = h.name_declared("name")``
``type = h.name_declared("name", 1)``
``type = h.name_declared("name", 2)``
Description:
Return 0 if the name is not in the NEURON/HOC symbol table. The first form looks
for names in the top level symbol table. The second form looks in the
current object context. The last form also looks in the top level
symbol table but is useful in Python to distinguish subtypes of
variables which appear as doubles in HOC but internally are really
not doubles and so cannot be pointed to by double*, eg. h.secondorder
which is <type 'int'> or h.nseg which returns either
``TypeError: Section access unspecified`` or
``nseg not a USERPROPERTY that can be pointed to``
If the name exists return
2 if an objref
3 if a Section
4 if a :ref:`strdef <keyword_strdef>`
5 if a scalar or :ref:`double <keyword_double>` variable. (if second arg is not 2)
if second arg is 2
5 if a scalar double
6 if a double array
7 if an integer
8 if a section property
1 otherwise
.. ::
A HOC work-around that is not relevant in Python.
Note that names can be (re)declared only if they do not already
exist or are already of the same type.
This is too useful to require the user to waste an objref in creating a
:class:`StringFunctions` class to use :meth:`~StringFunctions.is_name`.
.. code-block::
none
name_declared("nrnmainmenu_")
{object_push(nrnmainmenu_) print name_declared("ldfile", 0) object_pop()}
{object_push(nrnmainmenu_) print name_declared("ldfile", 1) object_pop()}
.. note::
This function checks the NEURON/HOC symbol table; Python objects are handled separately.
To test if a simple name is a local variable in Python, use:
.. code-block::
python
if 'soma' in locals():
# do something
Checking against ``globals()`` and ``dir()`` are also often useful.
If the name is known in advance, use a ``try``/``except`` block and catch NameError and AttributeError:
.. code-block::
python
try:
h.soma.squiggle
except (NameError, AttributeError):
print('Name does not exist')
Combining this with an ``eval`` can allow testing arbitrary names, but is potentially unsafe as it allows
execution of arbitrary code.
.. function:: symbols
Name:
symbols --- type the names of HOC functions and variables
Syntax:
``h.symbols()``
Description:
Types a list of functions and variable names defined in HOC. Dimensions
of arrays are also indicated.
.. warning::
No longer works. The nearest replacement is :func:`SymChooser` .
Object Related
.. function:: object_id
Syntax:
``h.object_id(objref)``
``h.object_id(objref, 1)``
Description:
Returns 0 if the object reference does not point to an object instance.
(Otherwise returns the pointer cast to a double, not a very useful number,
except that this is equal to the value returned by Python's ``hash`` function.)
If the second argument is 1, it returns the index of the object name. Returns
-1 if the object is the NULLObject.
Example:
.. code-block::
python
from neuron import h
a, b, c = h.List(), h.List(), h.Vector()
print(h.object_id(a)) # displays a double; equal to hash(a)
print(h.object_id(a, 1)) # 0 since a == h.List[0]
print(h.object_id(b, 1)) # 1 since b == h.List[1]
print(h.object_id(c, 1)) # 0 since c == h.Vector[0]
.. function:: allobjectvars
Syntax:
``h.allobjectvars()``
Description:
Prints all the HOC object references (objref variables) that have been
declared along with the class type of the object they reference and the
number of references. Objects created via Python and not assigned to a
HOC objref
Example:
.. code-block::
python
>>> h('objref foo')
1
>>> h.foo = h.Vector()
>>> h.allobjectvars()
obp hoc_obj_[0] -> NULL
obp hoc_obj_[1] -> NULL
obp foo[0] -> Vector[0] with 1 refs.
0.0
>>> banana = h.foo
>>> h.allobjectvars()
obp hoc_obj_[0] -> NULL
obp hoc_obj_[1] -> NULL
obp foo[0] -> Vector[0] with 2 refs.
0.0
.. function:: allobjects
Syntax:
``h.allobjects()``
``h.allobjects("templatename")``
``nref = h.allobjects(objectref)``
Description:
Prints the internal names of all class instances (objects) available
from the interpreter along with the number of references to them.
With a templatename the list is restricted to objects of that class.
With an object variable, nothing is printed but the reference count
is returned. The count is too large by one if the argument was of the
form templatename[index] since a temporary reference is created while
the object is on the stack during the call.
Example:
.. code-block::
python
>>> v = h.Vector()
>>> foo = h.List()
>>> h.allobjects()
List[0] with 1 refs
Vector[0] with 1 refs
0.0
>>> h.allobjects('Vector')
Vector[0] with 1 refs
0.0
>>> h.allobjects(foo)
2.0
.. function:: object_push
Syntax:
``h.object_push(objref)``
Description:
Enter the context of the object referenced by objref. In this context you
can directly access any variables or call any functions, even those not
declared as :ref:`public <keyword_public>`. Do not attempt to create any new symbol names!
This function is generally used by the object itself to save its state
in a session.
.. function:: object_pop
Syntax:
``h.object_pop()``
Description:
Pop the last object from an :func:`object_push` .
Miscellaneous
.. function:: hoc_pointer_
Syntax:
``h.hoc_pointer_(&variable)``
Description:
A function used by c and c++ implementations to request a pointer to
the variable from its interpreter name. Not needed by or useful for the user; returns 1.0 on
success.