Is this behaviour possible in Python?
class A():
def __init__(self, string):
self.string = string
def __???__(self):
return self.string
a = A("world")
hw = "hello "+a
print(hw)
>>> hello world
I am aware that I can do str(a), but I was wondering if it was possible to use 'a' as if it were a string-object.
This works for me:
class A(str):
def __init__(self, string):
super().__init__()
a = A('world')
hw = 'hello ' + a
print(hw)
Output:
hello world
Testing with a custom function added:
class A(str):
def __init__(self, string):
self.string = string
super().__init__()
def custom_func(self, multiple):
self = self.string * multiple
return self
a = A('world')
hw = 'hello ' + a
print(hw)
new_a = a.custom_func(3)
print(new_a)
Output:
hello world
worldworldworld
Or if you do not need to do anything on initiating the class:
class A(str):
pass
def custom_func(self, multiple):
self = self * multiple
return self
How about something like this? Using UserString from collections.
from collections import UserString
class MyString(UserString):
pass
test = MyString('test')
print(test)
print(test + 'test')
Do :
class A:
def __init__(self, string):
self.string = string
# __add__: instance + noninstance
# instance + instance
def __add__(self, string):
print('__add__')
return self.string + string
# __radd__: noninstance + instance
def __radd__(self, string):
print('__radd__')
return string + self.string
a = A("world")
hw = "hello " + a
print(1, hw)
hw = a + " hello"
print(2, hw)
hw = a + a
print(3, hw)
Output:
__radd__
(1, 'hello world')
__add__
(2, 'world hello')
__add__
__radd__
(3, 'worldworld')
collections.UserString__radd__to control the'..' +scenario.