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Performance Test: substring vs substr vs slice random
(version: 0)
Comparing performance of:
slice vs substring vs substr
Created:
6 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
var string = "I am the god of hellfire, and I bring you..."
Tests:
slice
var index = Math.floor(Math.random()*17); var substring = string.slice(index, index+8);
substring
var index = Math.floor(Math.random()*17); var substring = string.substring(index, index+8);
substr
var index = Math.floor(Math.random()*17); var substring = string.substr(index, 8);
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
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Test case name
Result
slice
substring
substr
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 break down what's being tested in this benchmark. The main goal of this benchmark is to compare the performance of three different methods for extracting substrings from a string: `substring`, `substr`, and `slice`. **Options compared:** * `substring()`: extracts a substring starting from the specified index up to the end of the string. * `substr()`: extracts a substring starting from the specified index with a specified length. (Note that this method is deprecated in modern JavaScript and is only included for comparison purposes.) * `slice()`: creates a new string by extracting a portion of another string, starting from the specified start index and with a specified end index. **Pros and Cons:** * **`substring()`**: This method can be slow because it uses the `split()` function internally to split the original string into an array of substrings. The `length` property is then used to get the desired substring. * **`substr()`**: As mentioned earlier, this method is deprecated in modern JavaScript and may not work as expected in some browsers or environments. However, it's included for comparison purposes, so we can still learn from its performance characteristics. In general, using `substr()` with a negative index can be faster than using `substring()`, but only if the length of the substring is equal to or less than the remaining part of the string. * **`slice()`**: This method is generally considered the fastest way to extract substrings because it's a native function that doesn't involve any additional overhead like `split()` or `substring()`. **Library usage:** None of these methods rely on external libraries. They are built-in functions in JavaScript. **Special JS features or syntax:** There are no special JS features or syntax used in this benchmark. The focus is solely on comparing the performance of different substring extraction methods. **Other alternatives:** If you need to extract substrings from a string, other alternatives include: * Using regular expressions (e.g., `str.match(/.../)`): While not as fast as native functions like `substring()` or `slice()`, regular expressions can be useful for more complex substring matching. * Using the `String.prototype.slice()` method with an array of indices: Instead of using a single index, you can pass an array of indices to extract multiple substrings in a single call. In summary, this benchmark helps compare the performance of three common methods for extracting substrings from a string: `substring()`, `substr()`, and `slice()`. By understanding how these methods work and their relative performance characteristics, developers can write more efficient code.
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