A complex or repeated expression or value that appears numerous times within a code block is put in a new variable using the refactoring technique “extract variable.” This approach reduces the risk of errors, improves code readability, and makes maintenance simpler by reducing redundant code.
Apply Extract Variable Technique
To refactor an Extract Variable, take the following actions:
- Determine the expression or value that is complicated or repeated that you want to extract into a variable.
- Pick a name that accurately describes the new variable.
- Create a new variable and give it a complicated or repetitive value or phrase.
- Replace the complex or repeating expression or value with the new variable in all cases.
Problem
observing a technique that uses a complicated calculation expression
Before Refactoring
def calculate_area(radius):
pi = 3.14
area = pi * radius * radius
return area
Solution
Just storing the value in a clearly defined variable and using that variable afterward should do.
After Refactoring
import math
def calculate_area(radius):
pi = math.pi
area = pi * radius * radius
return area
In this example, the code has been refactored to use the math module instead of hard-coding the value of pi. This makes the code more readable, maintainable, and less error-prone.
Drawbacks of Extract Variable Refactoring Technique
One potential problem with this technique is that extract variable refactoring occasionally results in an increase in the number of variables utilized in a code block, making the code more complex and difficult to understand. Additionally, if the extracted variable is not given a meaningful or descriptive name, it might be difficult to understand what it means.
Resolving Strategy
To avoid these problems, it is essential to carefully determine which phrases or values should be extracted into variables and to give the variables meaningful and illustrative names. Keep the following advised practices in mind when extracting variable refactoring:
- Give variables names that accurately reflect their functions and meanings.
- Avoid adding too many variables because doing so can make the code more difficult to read and comprehend.
- Make sure the variable is correctly scoped for its intended use by taking into account its scope.
- After reworking, make sure the code is still correct by performing extensive testing.
- To help find chances for Extract Variable refactoring and make sure the resulting code is efficient and maintainable, think about utilizing a code analysis tool.
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