Hello,
I was looking for a way to get info about func definition, esp. its param list.
The aim beeing to reproduce more or less its header line.
Found useful hints at
http://stackoverflow.com/questions/582056/getting-list-of-parameters-inside-python-function.
Example:
================================
import inspect
def func(a,b,c, d=4,e=5, *items,**params):
pass
argSpec = inspect.getargspec(func)
print argSpec
print inspect.formatargspec(argSpec)
print inspect.getsourcelines(func)
==>
"""
ArgSpec(args=['a', 'b', 'c', 'd', 'e'], varargs='items', keywords='params',
defaults=(4, 5))
((a, b, c, d, e), items, params, (4, 5))
(['def func(a,b,c, d=4,e=5, *items,**params):\n', ' pass\n'], 8)
"""
===============================
How does inspect do this magic?
Also:
print dir(argSpec)
# --> [... 'args', 'count', 'defaults', 'index', 'keywords', 'varargs']
What are (the methods) count and index supposed to provide?
doc:
-------------------------
inspect.getargspec(func)¶
Get the names and default values of a Python function’s arguments. A tuple
of four things is returned: (args, varargs, varkw, defaults). args is a list of
the argument names (it may contain nested lists). varargs and varkw are the
names of the * and ** arguments or None. defaults is a tuple of default
argument values or None if there are no default arguments; if this tuple has n
elements, they correspond to the last n elements listed in args.
Changed in version 2.6: Returns a named tuple ArgSpec(args, varargs,
keywords, defaults).
-------------------------
Finally, I found extremely complicated to rebuild the func headline:
================================
def namedArguments(argNames,defaultValues):
(s1,s2) = (len(argNames),len(defaultValues))
delta = s1 - s2
defaultExpr = lambda i: '' if i<0 or i>=s2 else "=%s" %(defaultValues[i])
return ', '.join( "%s%s" %(argNames[i],defaultExpr(i-delta)) for i in
range(s1) )
def headLine(f):
funcName = f.__name__
argNames, varargName, kwargName, defaultValues = inspect.getargspec(f)
namedArgs = namedArguments(argNames,defaultValues)
varargName = '' if varargName is None else ", *%s" %varargName
kwargName = '' if kwargName is None else ", **%s" %kwargName
return "%s(%s%s%s)" %(funcName,namedArgs,varargName,kwargName)
print headLine(func)
# ==> func(a, b, c, d=4, e=5, *items, **params)
================================
Maybe I'm overlooking an easier way to do that? (And why not built in the
module inspect?)
Denis
________________________________
vit esse estrany ☣
spir.wikidot.com
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