strfun.rst

StringFunctions (String Manipulation Class)

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:

from neuron import h
sf = h.StringFunctions() 

---

StringFunctions.len

Syntax:

length = strobj.len(str)

Description:

Return the length of a string.

Example:

from neuron import h
s = h.ref("hello")
sf = h.StringFunctions()
length = sf.len(s)
print(length)

---

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:

from neuron import h
s1 = h.ref("allowed")
s2 = h.ref("low")
sf = h.StringFunctions()
index = sf.substr(s1, s2)

---

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:

from neuron import h
s1 = h.ref("hello world")
s2 = h.ref("")
sf = h.StringFunctions()
index = sf.head(s1, "[e]", s2)
print(s2[0])

---

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:

from neuron import h
s1 = h.ref("hello world")
s2 = h.ref("")
sf = h.StringFunctions()
index = sf.tail(s1, "[e]", s2)
print(s2[0])

---

StringFunctions.right

Syntax:

strobj.right(str, n)

Description:

Removes first n characters from str and puts the result in str.

Example:

from neuron import h
s = h.ref("hello")
sf = h.StringFunctions()
sf.right(s, 3)
print(s[0])

---

StringFunctions.left

Syntax:

.left(str, n)

Description:

Removes all but first n characters from str and puts the result in str

Example:

from neuron import h
s = h.ref("hello")
sf = h.StringFunctions()
sf.left(s, 3)
print(s[0])

---

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 name_declared function (except that returns 1 or 0 instead of True or False).

Example:

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).

---

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:

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)

---

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:

from neuron import h
h.load_file('stdrun.hoc')
sf = h.StringFunctions()
v = h.Vector()
al = sf.alias_list(v)
print(al)

---

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 HBox, VBox, and List). It also prints the number of references found.

Example:

from neuron import h
s1 = h.Section(name='soma')
strobj = h.StringFunctions()
strobj.references(s1)

---

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 MechanismType(1) <MechanismType> list).

Example:

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))

---

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 MechanismType(1) <MechanismType> list).

Example:

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))