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Simple Split vs Match
(version: 0)
Comparing performance of:
Matching, with groups vs Split vs Matching, with look behind
Created:
4 years ago
by:
Guest
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Script Preparation code:
var str = 'r/funny'
Tests:
Matching, with groups
str.match(/\/(.)/)[1].toUpperCase()
Split
str.split('/')[1][0].toUpperCase()
Matching, with look behind
str.match(/(?<=\/)./)[0].toUpperCase()
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
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Test case name
Result
Matching, with groups
Split
Matching, with look behind
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'll break down the explanation into manageable sections. **Benchmark Definition and Script Preparation Code** The benchmark definition is a JSON object that contains metadata about the test case, such as its name and description. In this case, the benchmark is testing two different approaches to extract the first character from a string: splitting and using regular expressions with groups or look-behinds. The script preparation code is a JavaScript snippet that prepares the input data for the benchmark: ```javascript var str = 'r/funny'; ``` This code creates a sample string `str` containing the path `/r/funny`. **Options Compared** Two options are being compared: 1. **Split**: This approach uses the `split()` method to split the string into an array of substrings, and then accesses the first element (`[1]`) and converts it to uppercase. 2. **Matching with groups**: This approach uses regular expressions with groups (capturing parentheses `(.)` around the character) to match the first character of the string and extracts it using the `[1]` index. 3. **Matching with look behind**: This approach uses a negative look-behind assertion (`(?<=\\/)`) to match the character at the beginning of the string, without consuming any characters from the string. **Pros and Cons** Here's a brief summary of the pros and cons of each approach: * **Split**: + Pros: Easy to understand, straightforward implementation. + Cons: May have performance overhead due to creating an array of substrings. * **Matching with groups**: + Pros: Fast execution, efficient use of regular expressions. + Cons: Requires careful configuration of the regex pattern and capture groups. * **Matching with look behind**: + Pros: Can be more efficient than using `split()` or capturing groups, as it doesn't create an array. + Cons: May have issues with Unicode normalization and character encoding. **Library and Special JS Feature** There is no library explicitly mentioned in the benchmark definition. However, regular expressions are a built-in feature of JavaScript, and their syntax and behavior can vary across browsers and versions. **Test Cases and Device Platform** The test cases are designed to run on different devices: * **Matching with look behind**: This test case has the highest execution rate (6634245 executions/second) on Chrome 93 running on a Windows desktop. * **Matching with groups**: This test case has a moderate execution rate (6370916 executions/second) on Chrome 93 running on a Windows desktop. * **Split**: This test case has the lowest execution rate (3976964.5 executions/second) on Chrome 93 running on a Windows desktop. **Alternatives** Other alternatives for benchmarking regular expression performance could include: * Using different regex patterns or configurations * Adding more complex input data to test edge cases * Comparing performance across multiple browsers and versions * Incorporating other JavaScript features, such as async/await or promises
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