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Compare lastindexOf + substr vs split + slice1
(version: 0)
new
Comparing performance of:
1 vs 2
Created:
6 years ago
by:
Guest
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HTML Preparation code:
<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>
Tests:
1
var s = 'sdfsdfsdf.asdasdasdasdasd.1231231'; console.log(s.substr(s.lastIndexOf('.') + 1));
2
var s = 'sdfsdfsdf.asdasdasdasdasd.1231231'; console.log(_.last(s.split('.')));
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Result
1
2
Fastest:
N/A
Slowest:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided JSON and benchmark definition to understand what is being tested. **Benchmark Definition** The `Compare lastIndexOf + substr vs split + slice1` benchmark compares two approaches for extracting a substring from a string: 1. Using the `substr` method with `lastIndexOf` to extract the substring. 2. Using the `split` and `slice1` methods (from the Lodash library) to extract the substring. **Options Compared** The two options being compared are: * **Option 1:** `s.substr(s.lastIndexOf('.') + 1)` + This approach uses the `substr` method, which returns a subset of characters in the string starting at the specified position. + It extracts the substring from the original string `s`, starting after the last occurrence of `'.'`. * **Option 2:** `_.last(s.split('.'))` + This approach uses the Lodash library's `split` and `last` methods. + It splits the original string `s` into an array of substrings using the `'.'` as a separator. + Then, it extracts the last element (i.e., the substring) from this array. **Pros and Cons** **Option 1: Using `substr` with `lastIndexOf`** Pros: * Fast and efficient, as it only requires a single method call. * Works well for strings with a large number of substrings separated by `'.'`. Cons: * Requires manual handling of edge cases (e.g., what if the string doesn't contain any '.'?). * May be slower than other approaches that use built-in methods. **Option 2: Using `split` and `last` from Lodash** Pros: * More concise and readable code. * Handles edge cases automatically, as it uses a library-provided method to split the string. * May be faster than Option 1 due to optimized implementation in the Lodash library. Cons: * Requires loading an external library (Lodash), which may add overhead. * May have performance overhead due to the library's complexity. **Library and Its Purpose** The `lodash` library is a popular JavaScript utility library that provides a collection of functional programming helpers, including methods for working with arrays, objects, and strings. In this benchmark, Lodash is used to provide the `split` and `last` methods, which are used to extract the substring from the original string. **Special JS Feature or Syntax** There isn't any special JavaScript feature or syntax mentioned in the provided code. The use of `substr` and `split` is standard JavaScript syntax. **Other Alternatives** If you wanted to implement this benchmark without using Lodash, you could use other libraries or implementations that provide similar functionality, such as: * `String.prototype.split()` with a custom `last` method. * A simple implementation using regular expressions. However, these alternatives would likely be less concise and more error-prone than the original code, which uses Lodash's optimized methods.
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