Inline

Inline variable

Inline Variable refactoring replaces redundant variable usage with its initializer.

The variable must be initialized at declaration. If the initial value is modified somewhere in the code, only the occurrences before modification will be inlined.

import math


class Solver:
    def demo(self):
        a = 3
        b = 25
        c = 46

        # This variable will be inlined
        return_type_of_sqrt = math.sqrt(b ** 2 - 4 * a * c)
        root1 = (-b + return_type_of_sqrt) / (2 * a)
        root2 = (-b - return_type_of_sqrt) / (2 * a)
        print(root1, root2)


Solver().demo()

import math


class Solver:
    def demo(self):
        a = 3
        b = 25
        c = 46

        # This variable will be inlined
        root1 = (-b + math.sqrt(b ** 2 - 4 * a * c)) / (2 * a)
        root2 = (-b - math.sqrt(b ** 2 - 4 * a * c)) / (2 * a)
        print(root1, root2)


Solver().demo()

Inline method or function

Inline Method results in placing method's body into the body of its callers. When you initiate inline refactoring for a method or function, PyCharm prompts to choose whether to remove the method declaration after the refactoring or keep it intact. Depending on your choice, the refactoring results vary.

def say_state(self):
    print_state(self)


def print_state(self):
    print("I'm going {} kph!".format(self.speed))

def say_state(self):
    print("I'm going {} kph!".format(self.speed))

def say_state(self):
    print_state(self)


def print_state(self):
    print("I'm going {} kph!".format(self.speed))

def say_state(self):
    print("I'm going {} kph!".format(self.speed))


def print_state(self):
    print("I'm going {} kph!".format(self.speed))

When PyCharm discovers several occurrence of the method or function to inline, it enables refactoring preview. Click the Preview button in the Inline Refactoring dialog to evaluate the occurrences.

Click the Do Refactor button to complete inlining.

To inline a particular invocation, place the caret at it, press Ctrl+Alt+N, and select the Use this invocation only and keep the declaration option in the Inline Refactoring dialog.

Refactoring limitations

PyCharm doesn't not support inline refactoring for the following categories of methods and functions:

• Functions that are used as a decorator

• Functions that are used as a reference

• Functions that use any argument unpacking

• Generators

• Async functions

• Constructor calls

• Builtin functions

• Functions with decorators

• Recursive functions

• Functions with * arguments

• Overridden functions

• Functions with global variables

• Functions with nonlocal variables

• Functions with another function declaration

• Functions that interrupt control flow

When you try to perform refactoring for any of these functions or method, the warning message will be shown: