python - super() fails with error: TypeError "argument 1 must be type, not classobj" -


i error can't figure out. clue wrong sample code?

class b:     def meth(self, arg):         print arg  class c(b):     def meth(self, arg):         super(c, self).meth(arg)  print c().meth(1)

i got sample test code of 'super' built-in method. class "c"

here error:

traceback (most recent call last):   file "./test.py", line 10, in ?     print c().meth(1)   file "./test.py", line 8, in meth     super(c, self).meth(arg) typeerror: super() argument 1 must type, not classobj

fyi, here help(super) python itself:

help on class super in module __builtin__:  class super(object)  |  super(type) -> unbound super object  |  super(type, obj) -> bound super object; requires isinstance(obj, type)  |  super(type, type2) -> bound super object; requires issubclass(type2, type)  |  typical use call cooperative superclass method:  |  class c(b):  |      def meth(self, arg):  |          super(c, self).meth(arg)  |

your problem class b not declared "new-style" class. change so:

class b(object):

and work.

super() , subclass/superclass stuff works new-style classes. recommend in habit of typing (object) on class definition make sure new-style class.

old-style classes (also known "classic" classes) of type classobj; new-style classes of type type. why got error message saw:

typeerror: super() argument 1 must type, not classobj

try see yourself:

class oldstyle:     pass  class newstyle(object):     pass  print type(oldstyle)  # prints: <type 'classobj'>  print type(newstyle) # prints <type 'type'>

note in python 3.x, classes new-style. can still use syntax old-style classes new-style class. so, in python 3.x won't have problem.


Comments

Post a Comment

Popular posts from this blog

Email notification in google apps script -

https://support.google.com/docs/answer/91588?hl=en i have sheet the cells filled in data pulled via apps script, website. pull in exact same data, not. on old sheets version use able emails when data "changes" different value. new sheets, email when new data pasted cells, though exact same data......and, can't set @ ranges anymore, entire document. there easy way watch cells when data changes, , email myself? this looks lot you're trying do. for checking whether value has changed after edit, this gives necessary information it. hence, know whether new value same 1 or not. implementing "workaround" talked in second link, able compare , send email myself if value changed. initiate onedit trigger goes off onedit function uses these lines after checks in place have passed. var email = "xyz@whatever.com"; mailapp.sendemail(email, "triggermail", "a change has occurred in sheet"); note: sends "notification...
Read more

c++ - Difference between pre and post decrement in recursive function argument -

i have following sample code used pre-decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(--c); cout << c << endl; return; } } this function give output input 4 : dp3 dp2 dp1 dp0 0 1 2 3 but when use post decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(c--); cout << c << endl; return; } } output goes in infinite loop dp4 can explain me in detail why happens ? this happens because function(c--) called same value of c , when finishes c decremented. recursively called, hence called same value no chance of return , hit stack overflow error. assume this, int x = 1, y = 0; y = x++ result y == 1 , x == 2. if y = ++x , bot x , y 2.
Read more

javascript - IE11 incompatibility with jQuery's 'readonly'? -

the code i'm running has no issues in firefox, or chrome. user typing 1 textbox, tabs next , can continue typing that. when run webpage on ie11, user tabs next textbox , can't type in. textbox has double-clicked before user can insert anything. i've googled , seems ie give problems when using older jquery (i.e. prefers 'prop' 'attr' ). in code below jquery's readonly keyword being used in way ie11 no longer recognise/accept? i assume issue readonly , removeclass('ignore') working expected. //when focus on textbox 1 $("#field1").focus(function() { //remove readonly property textbox 1 $('#field1').prop('readonly', false).removeclass('ignore'); //add readonly property other textboxes $('#field2, #field3, #field4') .prop('readonly', 'readonly').addclass('ignore').val(''); }); i'm using jquery 2.1.3 ...
Read more