.. _strfun: StringFunctions (String Manipulation Class) ------------------------------------------- .. class:: StringFunctions Syntax: ``obj = h.StringFunctions()`` Description: The StringFunctions class contains functions which you can apply to a \ ``strdef``. This class exists purely for the utility of preventing pollution of name space with string operations. Example: .. code-block:: python from neuron import h sf = h.StringFunctions() ---- .. method:: StringFunctions.len Syntax: ``length = strobj.len(str)`` Description: Return the length of a string. Example: .. code-block:: python from neuron import h s = h.ref("hello") sf = h.StringFunctions() length = sf.len(s) print(length) ---- .. method:: StringFunctions.substr Syntax: ``index = strobj.substr(s1, s2)`` Description: Return the index into *s1* of the first occurrence of *s2*. If *s2* isn't a substring then the return value is -1. Example: .. code-block:: python from neuron import h s1 = h.ref("allowed") s2 = h.ref("low") sf = h.StringFunctions() index = sf.substr(s1, s2) ---- .. method:: StringFunctions.head Syntax: ``strobj.head(str, "regexp", result)`` Description: The result contains the head of the string up to but not including the *regexp*. returns index of last char. Example: .. code-block:: python from neuron import h s1 = h.ref("hello world") s2 = h.ref("") sf = h.StringFunctions() index = sf.head(s1, "[e]", s2) print(s2[0]) ---- .. method:: StringFunctions.tail Syntax: ``strobj.tail(str, "regexp", result)`` Description: The result contains the tail of the string from the char following *regexp* to the end of the string. return index of first char. Other functions can be added as needed, eg., \ ``index(s1, c1)``, \ ``char(s1, i)``, etc. without polluting the global name space. In recent versions functions can return strings. Example: .. code-block:: python from neuron import h s1 = h.ref("hello world") s2 = h.ref("") sf = h.StringFunctions() index = sf.tail(s1, "[e]", s2) print(s2[0]) ---- .. method:: StringFunctions.right Syntax: ``strobj.right(str, n)`` Description: Removes first n characters from *str* and puts the result in *str*. Example: .. code-block:: python from neuron import h s = h.ref("hello") sf = h.StringFunctions() sf.right(s, 3) print(s[0]) ---- .. method:: StringFunctions.left Syntax: ``.left(str, n)`` Description: Removes all but first n characters from *str* and puts the result in *str* Example: .. code-block:: python from neuron import h s = h.ref("hello") sf = h.StringFunctions() sf.left(s, 3) print(s[0]) ---- .. method:: StringFunctions.is_name Syntax: ``.is_name(item)`` Description: Returns True if the *item* is the name of a symbol, False otherwise. This is so useful that the same thing is available with the top level :func:`name_declared` function (except that returns 1 or 0 instead of True or False). Example: .. code-block:: python from neuron import h s1 = h.ref("hello world") sf = h.StringFunctions() name = sf.is_name(s1) print(name) Here is an example with one string that works, and another that does not: .. code-block:: python from neuron import h sf = h.StringFunctions() # valid name print(sf.is_name("xvalue")) # invalid name print(sf.is_name("xsquiggle")) .. note:: This is approximately equivalent to ``item in dir(h)``. ---- .. method:: StringFunctions.alias Syntax: ``.alias(obj, "name", &var2)`` ``.alias(obj, "name", obj2)`` ``.alias(obj, "name")`` ``.alias(obj)`` Description: "name" becomes a public variable for obj and points to the scalar var2 or object obj2. obj.name may be used anywhere the var2 or obj2 may be used. With no third arg, the "name" is removed from the objects alias list. With no second arg, the objects alias list is cleared. Example: .. code-block:: python from neuron import h sf = h.StringFunctions() v = h.Vector() sf.alias(v, 't', h._ref_t) print('v.t = %g' % v.t) h.t = 42 print('v.t = %g' % v.t) ---- .. method:: StringFunctions.alias_list Syntax: ``list = sf.alias_list(obj)`` Description: Return a new List object containing String objects which contain the alias names. .. warning:: The String class is not a built-in class. It generally gets declared when the nrngui.hoc file is loaded and lives in stdlib.hoc. Note that the String class must exist and its constructor must allow a single strdef argument. Minimally: Example: .. code-block:: python from neuron import h h.load_file('stdrun.hoc') sf = h.StringFunctions() v = h.Vector() al = sf.alias_list(v) print(al) ---- .. method:: StringFunctions.references Syntax: ``sf.references(object)`` Description: Prints the number of references to the object and all objref names that reference that object (including references via :class:`HBox`, :class:`VBox`, and :class:`List`). It also prints the number of references found. Example: .. code-block:: python from neuron import h s1 = h.Section(name='soma') strobj = h.StringFunctions() strobj.references(s1) ---- .. method:: StringFunctions.is_point_process Syntax: ``i = sf.is_point_process(object)`` Description: Returns 0 if the object is not a POINT_PROCESS. Otherwise returns the point type (which is always 1 greater than the index into the :func:`MechanismType(1) ` list). Example: .. code-block:: python from neuron import h h.load_file('stdrun.hoc') s1 = h.Section(name='soma') syn = h.ExpSyn(s1(0.5)) sf = h.StringFunctions() # not point process print(sf.is_point_process(s1)) # point process print(sf.is_point_process(syn)) c = h.IntFire1() # point process print(ssf.is_point_process(c)) ---- .. method:: StringFunctions.is_artificial Syntax: ``i = sf.is_artificial(object)`` Description: Returns 0 if the object is not an ARTIFICIAL_CELL. Otherwise returns the point type (which is always 1 greater than the index into the :func:`MechanismType(1) ` list). Example: .. code-block:: python from neuron import h h.load_file('stdrun.hoc') s1 = h.Section(name='soma') syn = h.ExpSyn(s1(0.5)) # initiate string function sf = h.StringFunctions() c = h.IntFire1() # artificial print(sf.is_artificial(c)) # not artificial print(sf.is_artificial(syn))