How to subclass a synchronized Queue with extra parameters
I am trying to subclass Queue and the following code throws an exception:
from Queue import Queue
class MyQueue(Queue, object):
def __init__(self, my_stuff = None):
super(MyQueue, self).__init__()
self.my_stuff = my_stuff
def my_function(self):
return self.my_stuff
And I'm calling it from __main__ like so:
a_queue = MyQueue(my_stuff = "some stuff")
print a_queue
I am getting, as expected:
$ ./my_queue.py
some stuff
But I only get that if I also inherit from object (per new-style classes). Otherwise I get:
Traceback (most recent call last):
File "./my_queue", line 13, in <module>
a_queue = MyQueue(my_stuff = "some stuff")
File "./my_queue", line 6, in __init__
super(MyQueue, self).__init__()
TypeError: must be type, not classobj
Why? It apparently doesn't work for Queue as easily as it does for e.g. mp.Process (see this question and also this question).
python-2.7
asked Nov 12 '18 at 22:21
Virgil GheorghiuVirgil Gheorghiu
13619
add a comment |
I am trying to subclass Queue and the following code throws an exception:
from Queue import Queue
class MyQueue(Queue, object):
def __init__(self, my_stuff = None):
super(MyQueue, self).__init__()
self.my_stuff = my_stuff
def my_function(self):
return self.my_stuff
And I'm calling it from __main__ like so:
a_queue = MyQueue(my_stuff = "some stuff")
print a_queue
I am getting, as expected:
$ ./my_queue.py
some stuff
But I only get that if I also inherit from object (per new-style classes). Otherwise I get:
Traceback (most recent call last):
File "./my_queue", line 13, in <module>
a_queue = MyQueue(my_stuff = "some stuff")
File "./my_queue", line 6, in __init__
super(MyQueue, self).__init__()
TypeError: must be type, not classobj
Why? It apparently doesn't work for Queue as easily as it does for e.g. mp.Process (see this question and also this question).
python-2.7
asked Nov 12 '18 at 22:21
Virgil GheorghiuVirgil Gheorghiu
13619
add a comment |
I am trying to subclass Queue and the following code throws an exception:
from Queue import Queue
class MyQueue(Queue, object):
def __init__(self, my_stuff = None):
super(MyQueue, self).__init__()
self.my_stuff = my_stuff
def my_function(self):
return self.my_stuff
And I'm calling it from __main__ like so:
a_queue = MyQueue(my_stuff = "some stuff")
print a_queue
I am getting, as expected:
$ ./my_queue.py
some stuff
But I only get that if I also inherit from object (per new-style classes). Otherwise I get:
Traceback (most recent call last):
File "./my_queue", line 13, in <module>
a_queue = MyQueue(my_stuff = "some stuff")
File "./my_queue", line 6, in __init__
super(MyQueue, self).__init__()
TypeError: must be type, not classobj
Why? It apparently doesn't work for Queue as easily as it does for e.g. mp.Process (see this question and also this question).
python-2.7
asked Nov 12 '18 at 22:21
Virgil GheorghiuVirgil Gheorghiu
13619
I am trying to subclass Queue and the following code throws an exception:
from Queue import Queue
class MyQueue(Queue, object):
def __init__(self, my_stuff = None):
super(MyQueue, self).__init__()
self.my_stuff = my_stuff
def my_function(self):
return self.my_stuff
And I'm calling it from __main__ like so:
a_queue = MyQueue(my_stuff = "some stuff")
print a_queue
I am getting, as expected:
$ ./my_queue.py
some stuff
But I only get that if I also inherit from object (per new-style classes). Otherwise I get:
Traceback (most recent call last):
File "./my_queue", line 13, in <module>
a_queue = MyQueue(my_stuff = "some stuff")
File "./my_queue", line 6, in __init__
super(MyQueue, self).__init__()
TypeError: must be type, not classobj
Why? It apparently doesn't work for Queue as easily as it does for e.g. mp.Process (see this question and also this question).
python-2.7
python-2.7
asked Nov 12 '18 at 22:21
Virgil GheorghiuVirgil Gheorghiu
13619
asked Nov 12 '18 at 22:21
Virgil GheorghiuVirgil Gheorghiu
13619
asked Nov 12 '18 at 22:21
Virgil GheorghiuVirgil Gheorghiu
13619
asked Nov 12 '18 at 22:21
Virgil GheorghiuVirgil Gheorghiu
13619
asked Nov 12 '18 at 22:21
Virgil GheorghiuVirgil Gheorghiu
13619
13619
add a comment |
add a comment |
1 Answer
1
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oldest
votes
The problem is that the Queue class does not support the super feature since it is an old style class.
This way inheriting from object will solve your problem (make it a new style class).
But if you want to avoid it just call init directly
change it to:
from Queue import Queue
class MyQueue(Queue):
def __init__(self, my_stuff = None):
Queue.__init__(self)
self.my_stuff = my_stuff
def my_function(self):
return self.my_stuff
while old classes in python cannot do this New style classes may use super(Foo, self) where Foo is the class and self is the instance.
super(type[, object-or-type])
Return a proxy object that delegates method calls to a parent or
sibling class of type. This is useful for accessing inherited methods
that have been overridden in a class. The search order is same as that
used by getattr() except that the type itself is skipped.
The new style class is usually a better choice
answered Nov 13 '18 at 9:54
Omer Ben HaimOmer Ben Haim
1216
Thanks, Omer. Please update the URLs in your answer to Python 2.7 and not Python 3.x, since I tagged the question with this version of Python.
– Virgil Gheorghiu
Nov 13 '18 at 17:26
thanks, done. if this answer solved your problem can you accept it?
– Omer Ben Haim
Nov 14 '18 at 10:13
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The problem is that the Queue class does not support the super feature since it is an old style class.
This way inheriting from object will solve your problem (make it a new style class).
But if you want to avoid it just call init directly
change it to:
from Queue import Queue
class MyQueue(Queue):
def __init__(self, my_stuff = None):
Queue.__init__(self)
self.my_stuff = my_stuff
def my_function(self):
return self.my_stuff
while old classes in python cannot do this New style classes may use super(Foo, self) where Foo is the class and self is the instance.
super(type[, object-or-type])
Return a proxy object that delegates method calls to a parent or
sibling class of type. This is useful for accessing inherited methods
that have been overridden in a class. The search order is same as that
used by getattr() except that the type itself is skipped.
The new style class is usually a better choice
answered Nov 13 '18 at 9:54
Omer Ben HaimOmer Ben Haim
1216
Thanks, Omer. Please update the URLs in your answer to Python 2.7 and not Python 3.x, since I tagged the question with this version of Python.
– Virgil Gheorghiu
Nov 13 '18 at 17:26
thanks, done. if this answer solved your problem can you accept it?
– Omer Ben Haim
Nov 14 '18 at 10:13
add a comment |
The problem is that the Queue class does not support the super feature since it is an old style class.
This way inheriting from object will solve your problem (make it a new style class).
But if you want to avoid it just call init directly
change it to:
from Queue import Queue
class MyQueue(Queue):
def __init__(self, my_stuff = None):
Queue.__init__(self)
self.my_stuff = my_stuff
def my_function(self):
return self.my_stuff
while old classes in python cannot do this New style classes may use super(Foo, self) where Foo is the class and self is the instance.
super(type[, object-or-type])
Return a proxy object that delegates method calls to a parent or
sibling class of type. This is useful for accessing inherited methods
that have been overridden in a class. The search order is same as that
used by getattr() except that the type itself is skipped.
The new style class is usually a better choice
answered Nov 13 '18 at 9:54
Omer Ben HaimOmer Ben Haim
1216
Thanks, Omer. Please update the URLs in your answer to Python 2.7 and not Python 3.x, since I tagged the question with this version of Python.
– Virgil Gheorghiu
Nov 13 '18 at 17:26
thanks, done. if this answer solved your problem can you accept it?
– Omer Ben Haim
Nov 14 '18 at 10:13
add a comment |
The problem is that the Queue class does not support the super feature since it is an old style class.
This way inheriting from object will solve your problem (make it a new style class).
But if you want to avoid it just call init directly
change it to:
from Queue import Queue
class MyQueue(Queue):
def __init__(self, my_stuff = None):
Queue.__init__(self)
self.my_stuff = my_stuff
def my_function(self):
return self.my_stuff
while old classes in python cannot do this New style classes may use super(Foo, self) where Foo is the class and self is the instance.
super(type[, object-or-type])
Return a proxy object that delegates method calls to a parent or
sibling class of type. This is useful for accessing inherited methods
that have been overridden in a class. The search order is same as that
used by getattr() except that the type itself is skipped.
The new style class is usually a better choice
answered Nov 13 '18 at 9:54
Omer Ben HaimOmer Ben Haim
1216
The problem is that the Queue class does not support the super feature since it is an old style class.
This way inheriting from object will solve your problem (make it a new style class).
But if you want to avoid it just call init directly
change it to:
from Queue import Queue
class MyQueue(Queue):
def __init__(self, my_stuff = None):
Queue.__init__(self)
self.my_stuff = my_stuff
def my_function(self):
return self.my_stuff
while old classes in python cannot do this New style classes may use super(Foo, self) where Foo is the class and self is the instance.
super(type[, object-or-type])
Return a proxy object that delegates method calls to a parent or
sibling class of type. This is useful for accessing inherited methods
that have been overridden in a class. The search order is same as that
used by getattr() except that the type itself is skipped.
The new style class is usually a better choice
answered Nov 13 '18 at 9:54
Omer Ben HaimOmer Ben Haim
1216
edited Nov 14 '18 at 10:11
answered Nov 13 '18 at 9:54
Omer Ben HaimOmer Ben Haim
1216
answered Nov 13 '18 at 9:54
Omer Ben HaimOmer Ben Haim
1216
answered Nov 13 '18 at 9:54
Omer Ben HaimOmer Ben Haim
1216
1216
Thanks, Omer. Please update the URLs in your answer to Python 2.7 and not Python 3.x, since I tagged the question with this version of Python.
– Virgil Gheorghiu
Nov 13 '18 at 17:26
thanks, done. if this answer solved your problem can you accept it?
– Omer Ben Haim
Nov 14 '18 at 10:13
add a comment |
Thanks, Omer. Please update the URLs in your answer to Python 2.7 and not Python 3.x, since I tagged the question with this version of Python.
– Virgil Gheorghiu
Nov 13 '18 at 17:26
thanks, done. if this answer solved your problem can you accept it?
– Omer Ben Haim
Nov 14 '18 at 10:13
Thanks, Omer. Please update the URLs in your answer to Python 2.7 and not Python 3.x, since I tagged the question with this version of Python.
– Virgil Gheorghiu
Nov 13 '18 at 17:26
Thanks, Omer. Please update the URLs in your answer to Python 2.7 and not Python 3.x, since I tagged the question with this version of Python.
– Virgil Gheorghiu
Nov 13 '18 at 17:26
thanks, done. if this answer solved your problem can you accept it?
– Omer Ben Haim
Nov 14 '18 at 10:13
thanks, done. if this answer solved your problem can you accept it?
– Omer Ben Haim
Nov 14 '18 at 10:13
add a comment |
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