Benchmark: Extract number from string

Script Preparation code:

var testString = "123.456 unit"

Tests:

Splitting
var values = testString.split(" "); var value1 = values[0];
parseFloat
var floats = Number.parseFloat(testString); var value1 = floats[0];
regex
var value1 = testString.match(/[-\d.]*/);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Splitting
parseFloat
regex

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_0_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0.1 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 17 on iOS 17.0.3

View result in a separate tab

Test name	Executions per second
Splitting	21168886.0 Ops/sec
parseFloat	6732353.5 Ops/sec
regex	22397304.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**
The benchmark definition provides three separate test cases:

1. **Extracting numbers from a string**: The script preparation code contains `var values = testString.split(" "); var value1 = values[0];`. This code splits the input string into an array of words, and then extracts the first word (assuming it's the number).
2. **Parsing floating-point numbers using parseFloat**: The script preparation code contains `var floats = Number.parseFloat(testString); var value1 = floats[0];`. This code attempts to parse the input string as a float using the `Number.parseFloat()` function, and then extracts the first parsed value.
3. **Extracting numbers from a string using regular expressions**: The script preparation code contains `var value1 = testString.match(/[-\\d.]*/);`. This code uses a regular expression to match one or more digits (`-`, `\d`, and `.`) in the input string, and extracts the matched value.

**Options Compared**
The benchmark compares three different approaches for extracting numbers from a string:

* **Splitting**: Using the `split()` method to split the string into an array of words and extract the first word.
* **parseFloat**: Parsing the string as a float using the `Number.parseFloat()` function.
* **Regular Expressions**: Using a regular expression to match one or more digits in the input string.

**Pros and Cons**

1. **Splitting**:
	* Pros: Simple, easy to implement, and works for simple cases where the number is followed by whitespace.
	* Cons: May not work correctly if the number is preceded by whitespace or other characters, and can be slower than other methods.
2. **parseFloat**:
	* Pros: More robust than splitting, as it can handle decimal numbers and other formats.
	* Cons: May not work correctly if the input string is not a valid float, and can be slower due to the parsing overhead.
3. **Regular Expressions**:
	* Pros: Can handle complex patterns, including decimal numbers and whitespace.
	* Cons: More complex to implement, and may not be as fast as other methods.

**Library**
None of the test cases use any external libraries.

**Special JavaScript Features or Syntax**
There are no specific features or syntax mentioned in the benchmark definition that would require special handling. However, it's worth noting that the regular expression used in the third test case (`/[-\\d.]*/`) uses some advanced regex features that may not be supported by all browsers.

**Other Alternatives**

* For extracting numbers from a string, other alternatives might include using a library like `mathjs` or `parse-number`.
* For parsing floating-point numbers, other alternatives might include using the `Float32Array` or `Float64Array` types in JavaScript.
* For regular expression-based extraction, other alternatives might include using a different regex pattern or exploring other matching techniques.

Overall, this benchmark provides a useful comparison of three common approaches for extracting numbers from strings in JavaScript.

Related benchmarks:

Extract number from string (version: 0)

Comparing performance of: Splitting vs parseFloat vs regex

Created: one year ago by: Guest

Jump to the latest result

Splitting

parseFloat

regex

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):