I'm trying to call a function from a class in python. This is my code:
class JCMT:
def be(self):
if self > 330000:
return 0.64
else:
return 0.69
def bs(self):
if self > 330000:
return 14
else:
return 20
f = 220258
print JCMT.bs(f)
I'm getting an error of TypeError: unbound method bs() must be called with JCMT instance as first argument (got int instance instead)
Could someone tell me where I'm going wrong?
Add a static method decorator right above the function to denote a static function called on the class:
@staticmethod
Problem is your self parameter corresponds to an instance object which is implicitly passed during function invocation and thus an error is thrown when a class is supplied instead. You must remove the self argument and use an argument to denote the numerical argument.
There were a few problems, I addressed them with comments:
class JCMT:
# Add parameter
def bs(self, n):
if n > 330000:
return 14
else:
return 20
f = 220258
# Make a new instance
j = JCMT()
# Call now, and pass variable
print j.bs(f)
The self part in the method signature is unique. You can read more about it in this answer.
Althout the @staticmethod decorator already provided in an answer solves this particular problem, if in the future you wish to use the class method and retain self, you can also use the @classmethod decorator to call the method directly without instantiating the class first.
class JCMT:
@classmethod
def be(self, n):
if n > 330000:
return 0.64
else:
return 0.69
@classmethod
def bs(self, n):
if n > 330000:
return 14
else:
return 20
f = 220258
print JCMT.bs(f)
20
