Benchmark: Extracted number from string back to string

Script Preparation code:

var testString = "123.456 unit"

Tests:

Splitting
var value = testString.split(" ")[0]; var result = "Final result: " + value;
parseFloat
var value = Number.parseFloat(testString); var result = "Final result: " + value;
regex
var value = testString.match(/[-\d.]*/); var result = "Final result: " + value;

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 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36

Browser/OS: Chrome 118 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Splitting	19184790.0 Ops/sec
parseFloat	8350915.0 Ops/sec
regex	4710788.5 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the JavaScript microbenchmark on MeasureThat.net.

**Benchmark Overview**

The benchmark measures the performance of three different approaches to extract a number from a string: splitting, using `parseFloat`, and using regular expressions.

**Options Compared**

1. **Splitting**: This approach involves splitting the input string into substrings separated by whitespace characters (`\s`) using the `split()` method. The first substring is then extracted and converted back to a string.
2. **parseFloat**: This approach uses the `parseFloat()` function to convert the numeric part of the input string to a floating-point number.
3. **Regex**: This approach uses regular expressions to extract the numeric part of the input string. Specifically, it matches any characters (`[-\\d.]*`) that are either digits (`\\d`), dot (`.`), or hyphen (`-`). The matched string is then extracted and converted back to a string.

**Pros and Cons**

1. **Splitting**:
	* Pros: Simple and straightforward.
	* Cons: May not work correctly if the input string contains non-whitespace characters before the numeric part, which may lead to incorrect results or errors.
2. **parseFloat**:
	* Pros: Robust and flexible.
	* Cons: May be slower than other approaches for small numbers due to the overhead of parsing a floating-point number.
3. **Regex**:
	* Pros: Flexible and powerful, can extract various types of numeric values (e.g., integers, floats).
	* Cons: Can be slower than other approaches for small numbers due to the complexity of regular expressions.

**Library Used**

None in this specific benchmark, as all tests are performed using built-in JavaScript functions.

**Special JS Features or Syntax**

There is no special JavaScript feature or syntax used in these tests. The focus is on comparing the performance of different approaches to extract a number from a string.

**Other Alternatives**

In addition to the three approaches mentioned above, there are other methods to extract numbers from strings, such as:

1. **Using `parseInt()`**: Similar to `parseFloat()`, but uses integer arithmetic instead.
2. **Using `match()` with a more complex regular expression**: Can be used to extract more specific types of numeric values (e.g., integers only).
3. **Using a custom parsing function**: A custom implementation that can handle various edge cases and performance optimizations.

These alternatives may offer better or worse performance depending on the use case, but are not compared in this benchmark.

Related benchmarks:

Extracted number from string back to 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):