Benchmark: Array duplicate removal for duplicates exceeding `N`-number

Tests:

original duplicate removal
// Remove duplicates that occur 3 or more times in an array // keeping unique values and those with less than 3 function removeMany(arr) { const newArr = Array.from(arr).sort() let count = 0; let result = [] newArr.forEach((value, index, ar) => { count += 1; // refactored afterwards from (ar[index + 1] !== value) if (ar.lastIndexOf(value) <= index && count <= 2) { for (var i = 0; i < arr.length; i++) { if (arr[i] === value) { result.push(arr[i]) } } count = 0 } else if (ar[index + 1] !== value) { count = 0; } }); // +1 is there anyway to return a result that mimicks the original order of `numbers`? return result; // [1, 2, 2, 3, 4, 4] } const numbers = [1, 2, 3, 2, 4, 4, 5, 5, 5, 5]; console.log(removeMany(numbers));
2-pass approach
// Remove duplicates that occur 3 or more times in an array // keeping unique values and those with less than 3 function removeMany(arr) { let countMappings = arr.reduce(function(carry, item) { if (carry[item]!== undefined) { carry[item]++; } else { carry[item] = 1; } return carry; }, {}); return arr.reduce(function(final, item) { if (countMappings[item] <3) { final.push(item); } return final; }, []); } const numbers = [1, 2, 3, 2, 4, 4, 5, 5, 5, 5]; console.log(removeMany(numbers));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
original duplicate removal
2-pass approach

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 7 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.79 Safari/537.36 Edge/14.14393

Browser/OS: Chrome 51 on Windows

View result in a separate tab

Test name	Executions per second
original duplicate removal	167509.2 Ops/sec
2-pass approach	254184.1 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

Measuring the performance of JavaScript microbenchmarks is crucial to optimize code execution and identify bottlenecks.

**Benchmark Overview**

The provided benchmark measures the performance of two approaches to remove duplicates from an array that occur 3 or more times:

1. **Original Duplicate Removal**: This approach sorts the array, iterates through it, and pushes unique values with a count less than 3 into a new result array.
2. **2-Pass Approach**: This approach uses a mapping object to count occurrences of each element in the array and then filters out elements that occur 3 or more times.

**Options Compared**

Both approaches have their pros and cons:

*   **Original Duplicate Removal**
    *   Pros:
        *   Simple and easy to understand
        *   No additional data structure is required (aside from a temporary result array)
    *   Cons:
        *   Sorts the entire array, which can be costly for large datasets
        *   May have performance issues if the array is very large or has many duplicate elements
*   **2-Pass Approach**
    *   Pros:
        *   More efficient than the original approach (especially for large arrays)
        *   Uses a mapping object to count occurrences, which reduces the number of iterations required
    *   Cons:
        *   Requires an additional data structure (the mapping object) to store counts
        *   May be more complex and harder to understand

**Library and Special JS Feature**

In this benchmark, there is no specific library or special JavaScript feature being tested. However, the 2-pass approach uses a common JavaScript technique called "mapping" or "counting," which is used to iterate through an array and perform calculations based on each element's value.

**Alternative Approaches**

Other possible approaches to remove duplicates from an array include:

*   Using `Set` data structure (e.g., `[...new Set(numbers)]`)
*   Using a `for...of` loop with a `reduce()` method
*   Using a library like Lodash or Ramda for functional programming

Keep in mind that each approach has its own trade-offs, and the best choice will depend on the specific requirements of your use case.

Related benchmarks:

Array duplicate removal for duplicates exceeding `N`-number (version: 0)

https://codereview.stackexchange.com/q/175067/120114

Comparing performance of: original duplicate removal vs 2-pass approach

Created: 7 years ago by: Guest

Jump to the latest result

original duplicate removal

2-pass approach

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):