defining class related question(s)

[python101]

class motion:
          def  __init__(self, velocity, distance):
                 self._v = velocity
                 self._s = distance
 
          def  returnTime(self):
                return self._v/float(self._s)
 
 
 

Now I would like to define a doubleTime = returnTime*2. I use the code below, it doesn't work

#
          def doubleTime(self)
                return returnTime(self)*2
 

How can I fix the second code

[bartonc]

class motion:
          def  __init__(self, velocity, distance):
                 self._v = velocity
                 self._s = distance
 
          def  returnTime(self):
                return self._v/float(self._s)
 
 
 

Now I would like to define a doubleTime = returnTime*2. I use the code below, it doesn't work

#
          def doubleTime(self)
                return returnTime(self)*2
 

How can I fix the second code

#
          def doubleTime(self)
                return self.returnTime() * 2
 

Python automatically fills in the first parameter (self) of class methods. It's probably the hardest thing to get used to when authoring classes.

[python101]

It got an error

<bound method motion.doubleTime of <__main__.motion instance at 0x015C0698>

[bartonc]

It got an error

<bound method motion.doubleTime of <__main__.motion instance at 0x015C0698>

Here it is after testing:

class motion:
    def  __init__(self, velocity, distance):
        self._v = velocity
        self._s = distance
 
    def  returnTime(self):
        return self._v/float(self._s)
 
    # had a missing semi colon here #
    def doubleTime(self):
        return self.returnTime() * 2
 
m = motion(1, 2)
print m.doubleTime()

[python101]

Working now. However, when I tried another similar one it did not work.

Assuming that I already had my class (Cal) and everything related defined correctly

def t(self):
    return self._Y//10
 
def v(self):
    return self_.Y-self._t()*10.0
 
#if I used the cal.v(), it will return
<bound method .....>>
 

[bartonc]

Working now. However, when I tried another similar one it did not work.

Assuming that I already had my class (Cal) and everything related defined correctly

def t(self):
    return self._Y//10
 
def v(self):
    return self_.Y-self._t()*10.0
 
#if I used the cal.v(), it will return
<bound method .....>>
 

It's hard to tell from what you have posted. I can tell you that
self_.Y looks wrong and it is not self._Y.