<p>In python, the <code>filter</code> and <code>map</code> functions (among others) are top-level (i.e. global) functions which take an iterable as an argument. However, in Kotlin they are extension functions defined upon iterable and collection classes. What are the advantages and disadvantages of these approaches?</p>

<data-structures><iterators>
Should functions like filter and map be members of a class or top-level functions?
<p><strong>Top-level advantages:</strong></p>
<ul>
<li>Global Availability: Since these functions are available globally, you can directly use them on any iterable without the need to import specific modules or extend the iterable classes.</li>
<li>Functional Programming: Python's top-level functions align well with the principles of functional programming, allowing you to compose functions easily and perform operations on collections using a functional style.</li>
<li>Type Flexibility: you can use these functions on any kind of iterable without having to convert to a list first.</li>
</ul>
<p><strong>Class member advantages:</strong></p>
<ul>
<li>Object-Oriented Paradigm: Kotlin's approach of using extension functions aligns well with the object-oriented paradigm. It allows you to extend the functionality of iterable and collection classes directly, making the code more intuitive and readable for object-oriented programmers.</li>
<li>Improved Readability: By being part of the iterable classes, the extension functions in Kotlin provide better readability and discoverability. They can be easily identified when working with collections, making the code more self-explanatory.</li>
</ul>

CC BY-SA 4.0
2023-05-18T17:41:33.403Z
2023-05-19T05:06:26.497Z
2023-05-19T05:06:26.497Z
The Thonnu
CC BY-SA 4.0
2023-05-18T21:43:01.313Z
Top-level also means you can use it on strings, generators, or similar and it is automatically converted to an iterable.
naffetS
# Should functions like filter and map be members of a class or top-level functions?
Posted by: username_0 on 2023-05-18
In python, the `filter` and `map` functions (among others) are top-level (i.e. global) functions which take an iterable as an argument. However, in Kotlin they are extension functions defined upon iterable and collection classes. What are the advantages and disadvantages of these approaches?
**Tags:** data-structures iterators
---
## 1 answers
### Answer by username_1 on 2023-05-18. Score: 4
**Top-level advantages:**

* Global Availability: Since these functions are available globally, you can directly use them on any iterable without the need to import specific modules or extend the iterable classes.
* Functional Programming: Python's top-level functions align well with the principles of functional programming, allowing you to compose functions easily and perform operations on collections using a functional style.
* Type Flexibility: you can use these functions on any kind of iterable without having to convert to a list first.

**Class member advantages:**

* Object-Oriented Paradigm: Kotlin's approach of using extension functions aligns well with the object-oriented paradigm. It allows you to extend the functionality of iterable and collection classes directly, making the code more intuitive and readable for object-oriented programmers.
* Improved Readability: By being part of the iterable classes, the extension functions in Kotlin provide better readability and discoverability. They can be easily identified when working with collections, making the code more self-explanatory.
> **Comments:**
> **username_2** (2023-05-18): Top-level also means you can use it on strings, generators, or similar and it is automatically converted to an iterable.  
---
