Python dot-syntax-functions based on condition

Question

Is it possible in python to call dot-syntax-function based on condition. Simple example to turn:

if condition:
  foo().bar().baz()
  lots_of_code()
else:
  foo().baz()
  lots_of_code()

def lots_of_code():
  # lots of code

into:

foo().(if condition: bar()).baz()
# lots of code only once

Answer 1

No, it is not possible.

The syntax for attribute reference is

attributeref ::=  primary "." identifier

Quoting the documentation ,

An attribute reference is a primary followed by a period and a name

name must be a regular Python identifier and identifiers can't contain special characters like ( .

However, you can use a simple conditional expression to select primary :

(foo().bar() if condition else foo()).baz()

It's equivalent to

if condition:
    primary = foo().bar()
else:
    primary = foo()

primary.baz()

Note that in this case we have to use parentheses, because attribute reference has higher precedence than conditional expression.

Answer 2

Since foo() is called in either case, start by doing so unconditionally. Save that object to f , with the intention of calling f.baz() . Before that, though, check your condition to see if f should really be the result of foo().bar() .

f = foo()
if condition:
    f = f.bar()
f.baz()