We Keep Coding

Is there a way to have a object type of your choice (i.e. LinkedEdge) hash as part of a 'union.set()' processing?

I have the following code and it works until it gets to the 'union.set()' part. It says, "unhashable type: 'LinkedEdge' " . I am not sure why this is the case since I have looked at other sources on the web and in reference books to know that the 'g.addVertex()' method and the 'g.addEdge()' method as well as the arguments being passed should lead correctly to an output like this:
5 Vertices: A C B E D
5 Edges: A>B:3 A>C:2 B>D:1 C>D:1 D>E:2
class LinkedEdge(object):
def __init__(self, fromVertex, toVertex, weight = None):
self._vertex1 = fromVertex
self._vertex2 = toVertex
self._weight = weight
self._mark = False
def clearMark(self):
self._mark = False
def __eq__(self, other):
if self is other: return True
if type(self) != type(other):
return False
return self._vertex1 == other._vertex1 and self._vertex2 == other._vertex2
def getOtherVertex(self, thisVertex):
if thisVertex == None or thisVertex == self._vertex2:
return self._vertex1
else:
return self._vertex2
def getToVertex(self):
return self._vertex2
def getWeight(self):
return self._weight
def isMarked(self):
return self._mark
def setMark(self):
self._mark = True
def setWeight(self, weight):
self._weight = weight
def __str__(self):
return str(self._vertex1) + ">" + str(self._vertex2) + ":" + str(self._weight)
class LinkedVertex(object):
def __init__(self, label):
self._label = label
self._edgeList = []
self._mark = False
def clearMark(self):
self._mark = False;
def getLabel(self):
return self._label
def isMarked(self):
return self._mark
def setLabel(self, label, g):
g._vertices.pop(self._label, None)
g._vertices[label] = self
self._label = label
def setMark(self):
self._mark = True
def __str__(self):
return str(self._label)
def addEdgeTo(self, toVertex, weight):
edge = LinkedEdge(self, toVertex, weight)
self._edgeList.append(edge)
def getEdgeTo(self, toVertex):
edge = LinkedEdge(self, toVertex)
try:
return self._edgeList[self._edgeList.index(edge)]
except:
return None
def incidentEdges(self):
return iter(self._edgeList)
def neighboringVertices(self):
vertices = []
for edge in self._edgeList:
vertices.append(edge.getOtherVertex(self))
return iter(vertices)
def removeEdgeTo(self, toVertex):
edge = LinkedEdge(self, toVertex)
if edge in self._edgeList:
self._edgeList.remove(edge)
return True
else:
return False
class LinkedDirectedGraph(object):
def __init__(self, collection = None):
self._vertexCount = 0
self._edgeCount = 0
self._vertices = {}
if collection != None:
for label in collection:
self.addVertex(label)
# Methods for clearing, marks, sizes, string rep
def clear(self):
self._vertexCount = 0
self._edgeCount = 0
self._vertices = {}
def clearEdgeMarks(self):
for edge in self.edges():
edge.clearMark()
def clearVertexMarks(self):
for vertex in self.vertices():
vertex.clearMark()
def isEmpty(self):
return self._vertexCount == 0;
def sizeEdges(self):
return self._edgeCount
def sizeVertices(self):
return self._vertexCount
def __str__(self):
result = str(self.sizeVertices()) + " Vertices: "
for vertex in self._vertices:
result += " " + str(vertex)
result += "\n";
result += str(self.sizeEdges()) + " Edges: "
for edge in self.edges():
result += " " + str(edge)
return result
def addVertex(self, label):
self._vertices[label] = LinkedVertex(label)
self._vertexCount += 1
def containsVertex (self, label):
return label in self._vertices
def getVertex(self, label):
return self._vertices[label]
def removeVertex(self, label):
removedVertex = self._vertices.pop(label, None)
if removedVertex is None:
return False
# Examine all vertices
for vertex in self.vertices():
if vertex.removeEdgeTo(removedVertex):
self._edgeCount -= 1
self._vertexCount -= 1
return True
def addEdge(self, fromLabel, toLabel, weight):
fromVertex = self.getVertex(fromLabel)
toVertex = self.getVertex(toLabel)
fromVertex.addEdgeTo(toVertex, weight)
self._edgeCount += 1
def containsEdge(self, fromLabel, toLabel):
return self.getEdge(fromLabel, toLabel) != None
def getEdge(self, fromLabel, toLabel):
fromVertex = self._vertices[fromLabel]
toVertex = self._vertices[toLabel]
return fromVertex.getEdgeTo(toVertex)
def removeEdge (self, fromLabel, toLabel):
fromVertex = self.getVertex(fromLabel)
toVertex = self.getVertex(toLabel)
edgeRemovedFlg = fromVertex.removeEdgeTo(toVertex)
if edgeRemovedFlg:
self._edgeCount -= 1
return edgeRemovedFlg
# Iterators
def edges(self):
result = set()
for vertex in self.vertices():
edges = vertex.incidentEdges()
result = result.union(set(edges))
return iter(result)
def vertices(self):
return iter(self._vertices.values())
def incidentEdges(self, label):
return self._vertices[label].incidentEdges()
def neighboringVertices(self, label):
return self._vertices[label].neighboringVertices
g = LinkedDirectedGraph()
# Insert vertices
g.addVertex("John")
g.addVertex("Sam")
g.addVertex("Megan")
g.addVertex("Jennifer")
g.addVertex("Rick")
# Insert weighted edges
g.addEdge("John", "Sam", 3)
g.addEdge("John", "Megan", 2)
g.addEdge("Sam", "Jennifer", 1)
g.addEdge("Megan", "Jennifer", 1)
g.addEdge("Jennifer", "Rick", 2)
print(g)

If you override __eq__, then Python intentionally makes your class unhashable, since there is no longer a guarantee that the default hashing algorithm (based on the object's location in memory) is compatible with your __eq__ algorithm. "Compatible" here just means that equal objects must have equal hashes. By default, nothing is equal, so when you make some things equal using an __eq__ method, you impose a requirement on what a proper hash function must do.
If you want a custom class with a custom __eq__ method to be hashable, you must implement a __hash__ method yourself.
It could be as simple as being based on the hash of the corresponding tuple:
def __hash__(self):
return hash((type(self), self._vertex1, self._vertex2))
The Python docs explain this here.

Finding Method for Binary Tree doesn't return anything

I have a Binary Tree and want to search for elements in it.
But for some reason i'm not getting any output and no error. Tried debugging as well but the code is always being executed until the end.
def find(self, i):
if self.__head is None:
return -1
else:
return self.__find(self.__head, i)
def __find(self, element, i):
if element is not None:
if i == element.value():
return 1
elif i < element.value():
self.__find(element.getLeft(), i)
else:
self.__find(element.getRight(), i)
else:
return -1
The code for the Elements is the following:
class BElement:
def __init__(self, i, v):
self.__id = i
self.__value = v
self.__left = None
self.__right = None
def id(self):
return self.__id
def value(self):
return self.__value
def getLeft(self):
return self.__left
def setLeft(self, l):
self.__left = l
def getRight(self):
return self.__right
def setRight(self, r):
self.__right = r
def __str__(self):
s = "{"
if self.__left is not None:
s = s + str(self.__left)
s = s + str(self.__id) + ":" + str(self.__value)
if self.__right is not None:
s = s + str(self.__right)
s = s + "}"
return s

remove the brackets() after value,left and right they are not methods.

Next function on iterator stalls program

The program below stalls at line:
m = MapH()
This is related with the function:
def next(self):
If redefined as (should be only two underscores):
def __next__(self):
Then, got error message:
instance has no next() method
When hitting the line:
for e in m:
The full code is below:
class MapEntryH:
def __init__(self, key, value):
self.key = key
self.value = value
class MapIteratorH:
def __init__(self,entryList):
self._myEntryList = entryList
self._currItem = 0
def __iter__(self):
return self
def __next__(self):
if self._currItem < len(self._myEntryList):
item = self._myEntryList[self._currItem]
self._currItem += 1
return item
else:
StopIteration
class MapH:
def __init__(self):
self._entryList = list()
def __len__(self):
return len(self._entryList)
def _findPosition(self,key):
for i in range(len(self)):
if self._entryList[i].key == key:
return i
return None
def __contains__(self,key):
ndx = self._findPosition(key)
return ndx is not None
def add(self,key,value):
ndx = self._findPosition(key)
if ndx is not None:
self._entryList[ndx].value = value
return False
else:
entry = MapEntryH(key,value)
self._entryList.append(entry)
return True
def valueOf(self, key):
ndx = self._findPosition(key)
assert ndx is not None, "Invalid map key"
return self._entryList[ndx].value
def remove(self,key):
ndx =self._findPosition(key)
assert ndx is not None,"Invalid map key"
self._entryList.pop(ndx)
def __iter__(self):
return MapIteratorH(self._entryList)
def test_Map():
m = MapH()
m.add(1,"arg")
m.add(2,"eeu")
m.add(3,"ale")
m.add(4,"sue")
m.add(5,"bra")
temp = m.remove(5)
m.add(5,"chl")
m.add(5,"bol")
temp = m.valueOf(5)
temp = m._findPosition(4)
for e in m:
print(e)
me = MapEntryH(1,"arg")
test_Map()
How do I support iteration like:
for e in m:
print(e)
Or containment like:
me = MapEntryH(1,"arg")
if me in m:
print me.value + " is on the map"

Class inheritance type checking after pickling in Python

Is there a sure-fire way to check that the class of an object is a sub-class of the desired super?
For Example, in a migration script that I'm writing, I have to convert objects of a given type to dictionaries in a given manner to ensure two-way compatability of the data.
This is best summed up like so:
Serializable
User
Status
Issue
Test
Set
Step
Cycle
However, when I'm recursively checking objects after depickling, I receive a Test object that yields the following results:
Testing data object type:
type(data)
{type}< class'__main.Test' >
Testing Class type:
type(Test())
{type}< class'__main.Test' >
Testing object type against class type:
type(Test()) == type(data)
{bool}False
Testing if object isinstance() of Class:
isinstance(data, Test)
{bool}False
Testing if Class isinstance() of Super Class:
isinstance(Test(), Serializable)
{bool}True
Testing isinstance() of Super Class::
isinstance(data, Serializable)
{bool}False
Interestingly, it doesn't appear to have any such problem prior to pickling as it handles the creation of dictionary and integrity hash just fine.
This only crops up with depickled objects in both Pickle and Dill.
For Context, here's the code in it's native environment - the DataCache object that is pickled:
class DataCache(object):
_hash=""
_data = None
#staticmethod
def genHash(data):
dataDict = DataCache.dictify(data)
datahash = json.dumps(dataDict, sort_keys=True)
return hashlib.sha256(datahash).digest()
#staticmethod
def dictify(data):
if isinstance(data,list):
datahash = []
for item in data:
datahash.append(DataCache.dictify(item))
elif isinstance(data,(dict, collections.OrderedDict)):
datahash = collections.OrderedDict()
for key,value in datahash.iteritems():
datahash[key]= DataCache.dictify(value)
elif isinstance(data, Serializable):
datahash = data.toDict()
else:
datahash = data
return datahash
def __init__(self, restoreDict = {}):
if restoreDict:
self.__dict__.update(restoreDict)
def __getinitargs__(self):
return (self.__dict__)
def set(self, data):
self._hash = DataCache.genHash(data)
self._data = data
def verify(self):
dataHash = DataCache.genHash(self._data)
return (self._hash == dataHash)
def get(self):
return self._data
Finally, I know there's arguments for using JSON for readability in storage, I needed Pickle's ability to convert straight to and from Objects without specifying the object type myself. (thanks to the nesting, it's not really feasible)
Am I going mad here or does pickling do something to the class definitions?
EDIT:
Minimal Implementation:
#!/usr/bin/python
# -*- coding: UTF-8 -*-
import requests
from aenum import Enum
import json # _tricks
import base64
import argparse
import os
import sys
import datetime
import dill
import hashlib
import collections
class Serializable(object):
def __init__(self, initDict={}):
if initDict:
self.__dict__.update(initDict)
def __str__(self):
return str(self.sortSelf())
def sortSelf(self):
return collections.OrderedDict(sorted(self.__dict__.items()))
def toDict(self):
return self.__dict__
def fromDict(self, dict):
# Not using __dict__.update(...) to avoid polluting objects with the excess data
varMap = self.__dict__
if dict and varMap:
for key in varMap:
if (key in dict):
varMap[key] = dict[key]
self.__dict__.update(varMap)
return self
return None
class Issue(Serializable):
def __init__(self, initDict={}):
self.id = 0
self.key = ""
self.fields = {}
if initDict:
self.__dict__.update(initDict)
Serializable.__init__(self)
def fieldToDict(self, obj, key, type):
if key in obj:
result = obj[key]
else:
return None
if result is None:
return None
if isinstance(result, type):
return result.toDict()
return result
def fromDict(self, jsonDict):
super(Issue, self).fromDict(jsonDict)
self.fields["issuetype"] = IssueType().fromDict(self.fields["issuetype"])
self.fields["assignee"] = User().fromDict(self.fields["assignee"])
self.fields["creator"] = User().fromDict(self.fields["creator"])
self.fields["reporter"] = User().fromDict(self.fields["reporter"])
return self
def toDict(self):
result = super(Issue, self).toDict()
blankKeys = []
for fieldName, fieldValue in self.fields.iteritems():
if fieldValue is None:
blankKeys.append(fieldName)
if blankKeys:
for key in blankKeys:
self.fields.pop(key, None)
result["fields"]["issuetype"] = self.fieldToDict(result["fields"], "issuetype", IssueType)
result["fields"]["creator"] = self.fieldToDict(result["fields"], "creator", User)
result["fields"]["reporter"] = self.fieldToDict(result["fields"], "reporter", User)
result["fields"]["assignee"] = self.fieldToDict(result["fields"], "assignee", User)
return result
class IssueType(Serializable):
def __init__(self):
self.id = 0
self.name = ""
def toDict(self):
return {"id": str(self.id)}
class Project(Serializable):
def __init__(self):
Serializable.__init__(self)
self.id = 0
self.name = ""
self.key = ""
class Cycle(Serializable):
def __init__(self):
self.id = 0
self.name = ""
self.totalExecutions = 0
self.endDate = ""
self.description = ""
self.totalExecuted = 0
self.started = ""
self.versionName = ""
self.projectKey = ""
self.versionId = 0
self.environment = ""
self.totalCycleExecutions = 0
self.build = ""
self.ended = ""
self.name = ""
self.modifiedBy = ""
self.projectId = 0
self.startDate = ""
self.executionSummaries = {'executionSummary': []}
class Step(Serializable):
def __init__(self):
self.id = ""
self.orderId = 0
self.step = ""
self.data = ""
self.result = ""
self.attachmentsMap = {}
def toDict(self):
dict = {}
dict["step"] = self.step
dict["data"] = self.data
dict["result"] = self.result
dict["attachments"] = []
return dict
class Status(Serializable):
def __init__(self):
self.id = 0
self.name = ""
self.description = ""
self.isFinal = True
self.color = ""
self.isNative = True
self.statusCount = 0
self.statusPercent = 0.0
class User(Serializable):
def __init__(self):
self.displayName = ""
self.name = ""
self.emailAddress = ""
self.key = ""
self.active = False
self.timeZone = ""
class Execution(Serializable):
def __init__(self):
self.id = 0
self.orderId = 0
self.cycleId = -1
self.cycleName = ""
self.issueId = 0
self.issueKey = 0
self.projectKey = ""
self.comment = ""
self.versionId = 0,
self.versionName = "",
self.executedOn = ""
self.creationDate = ""
self.executedByUserName = ""
self.assigneeUserName = ""
self.status = {}
self.executionStatus = ""
def fromDict(self, jsonDict):
super(Execution, self).fromDict(jsonDict)
self.status = Status().fromDict(self.status)
# This is already listed as Execution Status, need to associate and convert!
return self
def toDict(self):
result = super(Execution, self).toDict()
result['status'] = result['status'].toDict()
return result
class ExecutionContainer(Serializable):
def __init__(self):
self.executions = []
def fromDict(self, jsonDict):
super(ExecutionContainer, self).fromDict(jsonDict)
self.executions = []
for executionDict in jsonDict["executions"]:
self.executions.append(Execution().fromDict(executionDict))
return self
class Test(Issue):
def __init__(self, initDict={}):
if initDict:
self.__dict__.update(initDict)
Issue.__init__(self)
def toDict(self):
result = super(Test, self).toDict()
stepField = "CustomField_0001"
if result["fields"][stepField]:
steps = []
for step in result["fields"][stepField]["steps"]:
steps.append(step.toDict())
result["fields"][stepField] = steps
return result
def fromDict(self, jsonDict):
super(Test, self).fromDict(jsonDict)
stepField = "CustomField_0001"
steps = []
if stepField in self.fields:
for step in self.fields[stepField]["steps"]:
steps.append(Step().fromDict(step))
self.fields[stepField] = {"steps": steps}
return self
class Set(Issue):
def __init__(self, initDict={}):
self.__dict__.update(initDict)
Issue.__init__(self)
class DataCache(object):
_hash = ""
_data = None
#staticmethod
def genHash(data):
dataDict = DataCache.dictify(data)
datahash = json.dumps(dataDict, sort_keys=True)
return hashlib.sha256(datahash).digest()
#staticmethod
def dictify(data):
if isinstance(data, list):
datahash = []
for item in data:
datahash.append(DataCache.dictify(item))
elif isinstance(data, (dict, collections.OrderedDict)):
datahash = collections.OrderedDict()
for key, value in datahash.iteritems():
datahash[key] = DataCache.dictify(value)
elif isinstance(data, Serializable):
datahash = data.toDict()
else:
datahash = data
return datahash
def __init__(self, restoreDict={}):
if restoreDict:
self.__dict__.update(restoreDict)
def __getinitargs__(self):
return (self.__dict__)
def set(self, data):
self._hash = DataCache.genHash(data)
self._data = data
def verify(self):
dataHash = DataCache.genHash(self._data)
return (self._hash == dataHash)
def get(self):
return self._data
def saveCache(name, projectKey, object):
filePath = "migration_caches/{projectKey}".format(projectKey=projectKey)
if not os.path.exists(path=filePath):
os.makedirs(filePath)
cache = DataCache()
cache.set(object)
targetFile = open("{path}/{name}".format(name=name, path=filePath), 'wb')
dill.dump(obj=cache, file=targetFile)
targetFile.close()
def loadCache(name, projectKey):
filePath = "migration_caches/{projectKey}/{name}".format(name=name, projectKey=projectKey)
result = False
try:
targetFile = open(filePath, 'rb')
try:
cache = dill.load(targetFile)
if isinstance(cache, DataCache):
if cache.verify():
result = cache.get()
except EOFError:
# except BaseException:
print ("Failed to load cache from file: {filePath}\n".format(filePath=filePath))
except IOError:
("Failed to load cache file at: {filePath}\n".format(filePath=filePath))
targetFile.close()
return result
testIssue = Test().fromDict({"id": 1000,
"key": "TEST",
"fields": {
"issuetype": {
"id": 1,
"name": "TestIssue"
},
"assignee": "Minothor",
"reporter": "Minothor",
"creator": "Minothor",
}
})
saveCache("Test", "TestProj", testIssue)
result = loadCache("Test", "TestProj")
EDIT 2
The script in it's current form, now seems to work correctly with vanilla Pickle, (initially switched to Dill due to a similar issue, which was solved by the switch).
However, if you are here with this issue and require Dill's features, then as Mike noted in the comments - it's possible to change the settings in dill.settings to have Dill behave pickle referenced items only with joblib mode, effectively mirroring pickle's standard pickling behaviour.

Web2py Custom Validators

I am new to Web2py and am trying to use a custom validator.
class IS_NOT_EMPTY_IF_OTHER(Validator):
def __init__(self, other,
error_message='must be filled because other value '
'is present'):
self.other = other
self.error_message = error_message
def __call__(self, value):
if isinstance(self.other, (list, tuple)):
others = self.other
else:
others = [self.other]
has_other = False
for other in others:
other, empty = is_empty(other)
if not empty:
has_other = True
break
value, empty = is_empty(value)
if empty and has_other:
return (value, T(self.error_message))
else:
return (value, None)
I do not understand how to use it on my table:
db.define_table('numbers',
Field('a', 'integer'),
Field('b', 'boolean'),
Field('c', 'integer')
I want to use this in a way that 'c' cannot be left black when 'b' is ticked.

save the code on /modules/customvalidators.py
from gluon.validators import is_empty
from gluon.validators import Validator
class IS_NOT_EMPTY_IF_OTHER(Validator):
def __init__(self, other,
error_message='must be filled because other value '
'is present'):
self.other = other
self.error_message = error_message
def __call__(self, value):
if isinstance(self.other, (list, tuple)):
others = self.other
else:
others = [self.other]
has_other = False
for other in others:
other, empty = is_empty(other)
if not empty:
has_other = True
break
value, empty = is_empty(value)
if empty and has_other:
return (value, T(self.error_message))
else:
return (value, None)
then in models/db.py
from customvalidator import IS_NOT_EMPTY_IF_OTHER
db.define_table("foo",
Field('a', 'integer'),
Field('b', 'boolean'),
Field('c', 'integer')
)
# apply the validator
db.foo.c.requires = IS_NOT_EMPTY_IF_OTHER(request.vars.b)
Also, note that it can be done easily without the above validator.
Forget all the code above and try this simplified way
Version 2:
controllers/default.py
def check(form):
if form.vars.b and not form.vars.c:
form.errors.c = "If the b is checked, c must be filled"
def action():
form = SQLFORM(db.foo)
if form.process(onvalidation=check).accepted:
response.flash = "success"
return dict(form=form)