Let's say I have the following class:
class MyClass:
def __init__(self, text):
self.text = text
def strip(self):
strip_text = self.text.strip()
return strip_text
def reverse(self):
rev_text = self.text.strip()[::-1]
return rev_text
my_name = MyClass('todd ')
I want to able to to call the methods to this class like this:
my_name.strip().reverse()
However, when I do so, it throws an error. How do I go about chaining methods?
my_name.strip() returns a String, which has no reverse() function.
A quick way is just to make my_name.strip() a new Class object, and reverse that:
MyClass(my_name.strip()).reverse()
(However, IMO this is kludgy and there's a better (more pythonic) way to fix this in the Class definition(s) itself.)
Each function has to replace the wrapped string, then return self. At the end of the chain, you retrieve the final result.
class MyClass:
def __init__(self, text):
self.text = text
def strip(self):
self.text = self.text.strip()
return self
def reverse(self):
self.text = self.text.strip()[::-1]
return self
my_name.strip().reverse().text
As an alternative to mutating the existing object, a new instance can be returned at each step.
class MyClass:
def __init__(self, text):
self.text = text
def strip(self):
return MyClass(self.text.strip())
def reverse(self):
return MyClass(self.text.strip()[::-1])
my_name.strip()returns an ordinary string, which does not have a.reverse()method.