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

Latest run results:

Run details: (Test run date: 15 days ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:133.0) Gecko/20100101 Firefox/133.0

Browser/OS: Firefox 133 on Linux

View result in a separate tab

Test name	Executions per second
split	13533983.0 Ops/sec
regex	22511514.0 Ops/sec

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

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 2 months ago):