Am Mon, 20 Dec 2004 04:22:24 -0800 schrieb bearophileHUGS:
> I've seen that I'd like to
> have a function that tells me if a given data structure contains one or
> more cyclic references
Hi,
does this help you?
from types import *
def isrecursive(obj, dict=None):
if dict==None:
dict={}
mytype=type(obj)
if mytype in [GeneratorType, SliceType]:
obj=list(obj)
mytype=ListType
l=[]
MethodWrapperType=type(l.__delattr__)
if type(obj) in [NoneType, TypeType, BooleanType, IntType, LongType,
FloatType, ComplexType,
StringType, UnicodeType, FunctionType, CodeType,
ClassType, MethodType,
UnboundMethodType, BuiltinMethodType, BuiltinFunctionType,
ModuleType, FileType, XRangeType,
EllipsisType, TracebackType, FrameType, BufferType,
StringType, MethodWrapperType,
MethodWrapperType]:
return 0
myid=id(obj)
if dict.has_key(myid):
return 1
dict[myid]=1
for attr in dir(obj):
value=getattr(obj, attr)
if isrecursive(value, dict):
return 1
try:
for item in obj:
if isrecursive(item, dict):
return 1
except TypeError:
pass
try:
for key, value in obj.items():
if isrecursive(value, dict):
return 1
except AttributeError:
pass
return 0
def test_isrecursive():
s="sdf"
assert(not isrecursive(s))
l=[]
assert(not isrecursive(l))
l.append(l)
assert(isrecursive(l))
print "OK"
d={}
assert(not isrecursive(d))
d["foo"]=()
assert(not isrecursive(d))
d["foo2"]="foo2"
assert(not isrecursive(d))
d["foo3"]=d
assert(isrecursive(d))
if __name__=="__main__":
test_isrecursive()
--
Thomas Güttler, http://www.thomas-guettler.de/
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