Benchmark: slice vs regex - MeasureThat.net

Script Preparation code:

var strIn = '1234-12-34 05:27:56Z';
var strOut = '';
var regex = /\d{4}-(\d{2})-(\d{2}) (\d{2})/;

Tests:

slice
var month = strIn.slice(5, 7); var day = strIn.slice(8, 10); var hour = strIn.slice(11, 13);
regex
var [_, month, day, hour] = strIn.match(regex)
brackets
var month = strIn[5] + strIn[6]; var day = strIn[8] + strIn[9]; var hour = strIn[11] + strIn[12];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
regex
brackets

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided benchmark, "slice vs regex", tests the performance of three different approaches to extract specific parts from a string: using `slice()`, using regular expressions (`regex`), and using bracket notation (`brackets`). The goal is to determine which approach is the fastest.

**Options Compared**

1. **Slice Method**: This method uses the `slice()` function to extract specific parts of the string.
2. **Regex Method**: This method uses a regular expression to match specific patterns in the string and extracts the desired parts.
3. **Brackets Method**: This method uses bracket notation (`[]`) to access specific characters in the string.

**Pros and Cons of Each Approach**

1. **Slice Method**
	* Pros: Fast, lightweight, and easy to use for simple cases.
	* Cons: May not be as efficient for larger strings or more complex patterns.
2. **Regex Method**
	* Pros: Flexible and powerful for matching complex patterns, can handle a wide range of input formats.
	* Cons: Generally slower than `slice()` due to the overhead of compiling regular expressions, may be overkill for simple cases.
3. **Brackets Method**
	* Pros: Similar speed to `slice()`, easy to use, and doesn't require explicit string manipulation.
	* Cons: May not work as expected if the input string is not properly formatted or if it contains unexpected characters.

**Library Used**

In this benchmark, none of the methods rely on a specific library. However, regular expressions in JavaScript are implemented in the browser's engine, which may affect performance.

**Special JS Features/Syntax**

None mentioned explicitly, but note that JavaScript's `slice()` method is part of the ECMAScript standard and has been supported for a long time. Regular expressions (`regex`) are also a built-in feature in JavaScript and have their own syntax rules. Bracket notation (`brackets`) is not a specific library or feature in this context.

**Other Alternatives**

For larger-scale string manipulation, alternative approaches might include:

1. **Using `substring()`**: Another string method that can be used for substring extraction.
2. **Using `indexOf()`, `lastIndexOf()`, and concatenation**: For extracting substrings based on specific patterns or positions in the string.

In summary, this benchmark tests three common methods for extracting parts from a string: using `slice()`, regular expressions (`regex`), and bracket notation (`brackets`). While each approach has its pros and cons, the slice method is generally considered the most efficient for simple cases.

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.6 Safari/605.1.15

Browser/OS: Safari 16 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
slice	9426594.0 Ops/sec
regex	6610095.5 Ops/sec
brackets	5317687.5 Ops/sec

Related benchmarks:

slice vs regex (version: 0)

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Comparing performance of: slice vs regex vs brackets

Created: 3 years ago by: Guest

Jump to the latest result

slice

regex

brackets

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):