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precompiled regexp vs inline (string split)
(version: 0)
precompiled regexp vs inline (string split)
Comparing performance of:
regex inline split vs regex precompiled split
Created:
5 years ago
by:
Guest
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Script Preparation code:
teststr = 'abc def 123 "moo moo" cow foo 2:1 1x test bar'; rex = /\s+|(!?".+?)"/
Tests:
regex inline split
teststr.split(/\s+|(!?".+?)"/)
regex precompiled split
teststr.split(rex)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
regex inline split
regex precompiled split
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the explanation of the benchmark. **What is tested?** The provided JSON represents two test cases that compare the performance of JavaScript regular expressions (regex) with different approaches: inline regex and precompiled regex. The tests are designed to measure which approach provides better performance for splitting a string using the `/\\s+|(!?\".+?)\"/` regex pattern. **Options compared** The benchmark compares two options: 1. **Inline regex**: In this approach, the regex pattern is defined directly inside the `split()` method. 2. **Precompiled regex**: In this approach, the regex pattern is defined outside of the `split()` method using a separate variable (`rex`). **Pros and cons of each approach** * **Inline regex**: + Pros: Reduces code size, makes it easier to read, and eliminates the need for an additional variable. + Cons: Can be slower due to the overhead of parsing and compiling the regex pattern inside the `split()` method. * **Precompiled regex**: + Pros: Can be faster since the regex pattern is already parsed and compiled when it's defined, reducing overhead. + Cons: Requires an additional variable for storing the precompiled regex pattern, which may add to code size. **Library usage** In this benchmark, a library (likely a built-in JavaScript function) is used for string splitting. The `split()` method itself doesn't use any external libraries. **Special JS features or syntax** The benchmark uses special JS feature: backtracking in regular expressions (`(!?\".+?)\"`). This means that the regex engine will try all possible combinations of characters to match the pattern, which can lead to slower performance. **Other considerations** When choosing between inline and precompiled regex approaches, consider the trade-off between code size and performance. If code size is a concern, inline regex might be a better choice. However, if performance is critical, precompiled regex could provide a slight advantage due to reduced overhead. As for alternatives, other ways to optimize string splitting include: * Using `String.prototype.split()` with a custom separator or regular expression. * Implementing a custom string splitting algorithm using loop-based approach. * Utilizing optimized string manipulation libraries (e.g., Apache Commons Lang). The benchmark's design allows users to compare the performance of these different approaches, providing valuable insights into optimization strategies for their own JavaScript code.
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Regex Exec vs String Split
RegEx.test (with inline regex) vs. String.includes vs. String.match
RegEx.test vs. Inline RegEx.test
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