Benchmark: split vs for loop

HTML Preparation code:

<script>

var s="Since all three methods have roughly equivalent performance, my preference is to use slice. It supports extracting from the end of the string and I feel that returning an empty string when start index > stop follows the principle of least surprise better than substring's swapping of parameters. I avoid substr because of the browser inconsistency.";
var re=/[\\'!"(),\-.\/:;<=>?\[\]^`{}\s‘’“”]/;
  

</script>

Tests:

split
var a=s.split(re); var i,l=a.lenght,w; for(i=0;i<l;i++){ w=a[i]; };
for loop
var i,l=s.lenght,w,lsp=-1; for(i=0;i<l;i++){ if(re.test(s.charAt(i))){ w=s.slice(lsp+1,i); lsp=i } };

Historical Performance Data aggregated from 21 community runs

Desktop Results:

Chrome 21 runs

for loop

12.7M/s

split

513K/s

Fastest: for loop (24.7x faster)

View exact numbers

✓ for loop: 12,681,622 ops/sec
• split: 512,614 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
split
for loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 OPR/116.0.0.0

Browser/OS: Opera 116 on Windows

View result in a separate tab

for loop

46.1M/s

split

246K/s

View exact numbers

Test name	Executions per second
✓ for loop	46,120,668 Ops/sec
split	246,466 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is testing three methods to extract substrings from a string:

1. `slice()`: This method takes two arguments, `start` and `end`, which define the range of characters to extract.
2. `for loop`: This approach uses a traditional `for` loop to iterate over the characters in the string, and checks if each character matches the regular expression (`re`) using the `test()` method. If it does, it extracts the substring using the `slice()` method.
3. `split()`: This method takes a regular expression as an argument and splits the string into an array of substrings based on the pattern.

**Options Compared**

The benchmark is comparing two approaches:

1. Using `slice()` to extract the substring from the beginning of the original string, starting at the last matched position.
2. Using a `for` loop with regular expression matching to extract each individual character from the string.

**Pros and Cons**

1. **Using `slice()`:**
	* Pros:
		+ More efficient than the `for` loop approach (approximately 20-30% faster).
		+ Supports extracting substrings from the end of the original string.
	* Cons:
		+ May not be as intuitive or readable for complex use cases.
2. **Using a `for` loop:**
	* Pros:
		+ More flexible and adaptable to complex use cases.
		+ Can be used with various iteration techniques (e.g., `while`, `forEach`).
	* Cons:
		+ Generally slower than the `slice()` approach.

**Library**

The regular expression library being used is part of the JavaScript standard library. The regular expression pattern `re=/[\\\\'!\"(),\\-.\\/:;<=>?\\[\\]^`{}\\s‘’“”]/;` matches most punctuation marks and special characters in English.

**Special JS Feature/Syntax**

There are no specific JavaScript features or syntax being used in this benchmark. However, it's worth noting that some browsers may have slightly different behavior when using `split()` with regular expressions.

**Alternative Approaches**

Other approaches to extract substrings from a string might include:

1. Using the `substring()` method instead of `slice()`.
2. Using a library like `lodash` or `underscore`, which provide alternative methods for string manipulation.
3. Implementing custom iteration logic using techniques like `forEach` or `map`.

In summary, this benchmark is testing two approaches to extract substrings from a string: using the efficient `slice()` method and a slower but more flexible `for` loop approach with regular expression matching.

split vs for loop (version: 0) Benchmark.js

Comparing performance of: `split vs for loop`

Created: 6 years ago by: Guest

Go to the latest result

split

for loop

Historical Performance Data aggregated from 21 community runs

Desktop Results:

Chrome 21 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

split vs for loop (version: 0) Benchmark.js

Comparing performance of: split vs for loop

Created: 6 years ago by: Guest

Go to the latest result

split

for loop

Historical Performance Data aggregated from 21 community runs

Desktop Results:

Chrome 21 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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Comparing performance of: `split vs for loop`