GCI12000 [Team TREE][2025] - For loop vs list comprehension

CHANGELOG.md

@@ -11,6 +11,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - [#400](https://github.com/green-code-initiative/creedengo-rules-specifications/pull/400) Add rule GCI535 - Prefer usage of Intl.NumberFormat
 
+### Added
+- [#407](https://github.com/green-code-initiative/creedengo-rules-specifications/pull/407): Detect a for loop and suggest a list comprehension
+
 ### Changed
 
 ### Deleted

RULES.md

@@ -87,6 +87,7 @@ Some are applicable for different technologies.
 | GCI535   | Use native Intl.NumberFormat to format numbers                    | There's no need to use a library to display formatted numbers in a recent browser. Use Intl.NumberFormat for that use case.                                                                                                                                                                                                                                                                                                   |                                                                                                                                                                         | 🚫   | 🚫  | 🚧 | 🚫     | 🚫   | 🚫 | 🚫   |
 
 
+| GCI1200 | To use list comprehension instead for loop in simple iterations  |    |    | ❓  | ❓      | 🚀    | ❓  | ❓  |❓  |❓  |
 
 ## Rules to be reworked / measured / clarified
 

src/main/rules/GCI1200/GCI1200.json

@@ -0,0 +1,15 @@
+{
+    "title": "Use list comprehension instead for loop in simple iterations",
+    "type": "CODE_SMELL",
+    "status": "ready",
+    "remediation": {
+      "func": "Constant\/Issue",
+      "constantCost": "5min"
+    },
+    "tags": [
+      "creedengo",
+      "eco-design",
+      "performance"
+    ],
+    "defaultSeverity": "Minor"
+  }

src/main/rules/GCI1200/python/GCI1200.asciidoc

@@ -0,0 +1,50 @@
+When you use a for loop, on every iteration, you have to look up the variable holding
+the list and then call its append() function. A list comprehension can be faster 
+than a for loop because it’s optimized for performance by Python’s internal mechanisms.
+
+== Non Compliant Code Example
+[source,python]
+----
+result = []
+for i in range(0,20):
+    result.append(i)
+----
+
+== Compliant Solution
+[source,python]
+----
+result = [i for i in range(0,20)]
+----
+
+== Relevance Analysis
+
+This rule is relevant for scenarios where is needed a simple iteration.
+The list comprehensions are often not only more readable
+but also faster than using "for loops."
+They can simplify the code, but if you put too much logic inside,
+they will instead become harder to read and understand.
+
+=== Configuration
+
+* Processor: Apple M1
+* RAM: 16 Go 
+* CO2 Emissions Measurement: Using https://mlco2.github.io/codecarbon/[CodeCarbon]
+
+=== Context
+
+Two approaches were benchmarked:
+- *Non-compliant:* For loop
+- *Compliant:* List comprehension
+
+=== Impact Analysis
+
+image::results.png[]
+
+== Conclusion
+
+The result of the tests determinated that the list comprehensions
+can be more readable, but also an alternative to reduce the C02 emissions.
+
+== References
+
+- https://realpython.com/list-comprehension-python/