Why Python allows comparison of a callable and a number?

[一首诗]

I used python to write an assignment last week, here is a code snippet

#================================

def departTime():
'''
Calculate the time to depart a packet.
'''
if(random.random < 0.8):
t = random.expovariate(1.0 / 2.5)
else:
t = random.expovariate(1.0 / 10.5)
return t

#================================

Can you see the problem? I compare random.random with 0.8, which
should be random.random().

Of course this because of my careless, but I don't get it. In my
opinion, this kind of comparison should invoke a least a warning in
any programming language.

So why does python just ignore it?

 

[Chris Rebert]

I used python to write an assignment last week, here is a code snippet

#================================

def departTime():
   '''
   Calculate the time to depart a packet.
   '''
   if(random.random < 0.8):
       t = random.expovariate(1.0 / 2.5)
   else:
       t = random.expovariate(1.0 / 10.5)
   return t

#================================

Can you see the problem?  I compare random.random with 0.8,  which
should be random.random().

Of course this because of my careless, but I don't get it.  In my
opinion, this kind of comparison should invoke a least a warning in
any programming language.

So why does python just ignore it?

It's an historical anomaly that's been rectified in Python 3, where
such non-equality comparisons between unrelated types *do* now raise
an error.

Cheers,
Chris

 

[MRAB]

I used python to write an assignment last week, here is a code snippet

#================================

def departTime():
'''
Calculate the time to depart a packet.
'''
if(random.random < 0.8):
t = random.expovariate(1.0 / 2.5)
else:
t = random.expovariate(1.0 / 10.5)
return t

#================================

Can you see the problem? I compare random.random with 0.8, which
should be random.random().

Of course this because of my careless, but I don't get it. In my
opinion, this kind of comparison should invoke a least a warning in
any programming language.

So why does python just ignore it?

In Python 2 you can compare any 2 objects, for example an int with a
string. The result is arbitrary but consistent.

In Python 3 if the 2 objects aren't 'compatible' you'll get a TypeError
at runtime.

BTW, you don't need to put parentheses around the conditions in 'if' and
'while' statements. Python isn't C, etc.