Benchmark: str split vs regex replace

Script Preparation code:

var str = '1234563242347.341342345';
var regex = /\..*$/;

Tests:

split
str.split('.')[0];
regex
str.replace(regex, '');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
split
regex

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation.

**Benchmark Overview**

The provided benchmark is designed to compare two approaches for splitting or replacing a string: using the `str.split()` method versus using regular expressions (regex). The goal of this benchmark is to determine which approach performs better in terms of execution speed.

**Options Compared**

Two options are compared:

1. **`str.split('.')[0]`**: This option uses the `split()` method with a dot (`.`) as the separator and then selects the first substring using indexing (`[0]`). The purpose of this method is to split the input string at the decimal point and return only the part before the decimal.
2. **`str.replace(regex, '')`**: This option uses regular expressions (regex) to replace all occurrences of a pattern with an empty string (`''`). In this case, the regex pattern `\\..*//` is used to match any character followed by zero or more asterisks (`.*`), effectively removing everything after the first dot (`.`).

**Pros and Cons**

Both approaches have their trade-offs:

1. **`str.split('.')[0]`**:
	* Pros: Simple, easy to understand, and widely supported.
	* Cons: May not work correctly for strings containing multiple dots or different separators (e.g., commas).
2. **`str.replace(regex, '')`**:
	* Pros: Flexible and can handle complex patterns, but may be slower due to the overhead of regular expressions.
	* Cons: Can be more difficult to read and understand, especially for beginners.

**Other Considerations**

When choosing between these two approaches, consider the following:

1. **Complexity**: If you need to handle strings with multiple dots or different separators, `str.split('.')[0]` might not work as expected.
2. **Performance**: For large datasets or high-performance applications, using regular expressions might incur additional overhead, making `str.split('.')[0]` a better choice.

**Library and Special JS Features**

The benchmark uses the `str` variable to represent the input string and defines two scripts: one for splitting and another for replacing. There are no external libraries used in this benchmark. Additionally, there are no special JavaScript features mentioned (e.g., async/await, arrow functions).

**Alternative Approaches**

If you need to handle similar tasks, consider these alternative approaches:

1. **Using `str.match()` instead of `split()`:**
```javascript
var match = str.match(/^...$/);
```
This approach matches the pattern at the beginning (`^`) and end (`$`) of the string using regular expressions.
2. **Using a library like Moment.js for date manipulation:**
Moment.js provides a convenient API for working with dates, including parsing decimal points.

Keep in mind that these alternatives may have different performance characteristics or requirements compared to the original benchmark.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:87.0) Gecko/20100101 Firefox/87.0

Browser/OS: Firefox 87 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
split	7527905.5 Ops/sec
regex	10870634.0 Ops/sec

Related benchmarks:

str split vs regex replace (version: 0)

Comparing performance of: split vs regex

Created: 3 years ago by: Guest

Jump to the latest result

split

regex

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):