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Testing lastIndexOf vs split+pop
(version: 0)
Comparing performance of:
lastIndexOf vs split+pop
Created:
7 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var str="abc:cde:def:efg:ghi";
Tests:
lastIndexOf
const lastIndexOfDot = str.lastIndexOf(':'); let snip; if (lastIndexOfDot != -1) { snip = str.substr(lastIndexOfDot + 1); } console.log(snip);
split+pop
let snip = str.split(':').pop(); console.log(snip);
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
lastIndexOf
split+pop
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36
Browser/OS:
Chrome 137 on Mac OS X 10.15.7
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<iframe src="https://measurethat.net/Embed?id=614143" width="100%" height="500px"></iframe>
lastIndexOf
708K/s
split+pop
702K/s
View exact numbers
Test name
Executions per second
✓
lastIndexOf
708,085 Ops/sec
split+pop
701,624 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the benchmark and explain what's being tested, compared, and some of the considerations. **Benchmark Context** MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The goal is to compare the performance of different approaches for a specific task or operation. **Script Preparation Code** The script preparation code is provided as `var str = "abc:cde:def:efg:ghi";;`. This creates a string variable `str` containing a colon-separated list of strings, which will be used in the benchmark tests. **Benchmark Definition** The benchmark definition provides two test cases: 1. **lastIndexOf**: Uses the `lastIndexOf()` method to find the last occurrence of a colon (`:`) in the `str` variable and then extracts a substring starting from the found index + 1. 2. **split+pop**: Splits the `str` string into an array using colons as delimiters, and then uses the `pop()` method to extract the last element of the array. **Comparison** The benchmark compares the performance of these two approaches: * `lastIndexOf`: Uses a more traditional approach that searches for a specific character (colon) in the string and then extracts a substring. * `split+pop`: Uses a more modern approach that splits the string into an array and then uses the `pop()` method to extract the last element. **Pros and Cons** **LastIndexOf Approach:** Pros: * Easy to understand and implement * Suitable for finding specific characters or patterns in strings Cons: * Can be slower than other approaches, especially for large strings or complex patterns * May have performance issues if the search string is very long or contains many occurrences of the target character **Split+Pop Approach:** Pros: * Often faster and more efficient than traditional `lastIndexOf()` approach * Suitable for finding the last occurrence of a specific value in an array Cons: * Requires splitting the string into an array, which can be slower for very large strings * May not work as expected if the target value is not found, resulting in `undefined` or other unexpected values **Library: None** No JavaScript library is used in this benchmark. **Special JS Features/Syntax: None** There are no special JavaScript features or syntax used in this benchmark. The tests only rely on basic string operations and standard JavaScript methods. **Alternatives** Other alternatives for finding the last occurrence of a character or value in a string include: * Using regular expressions with `String.prototype.lastIndexOf()` method * Using a more modern approach like using a `Map` data structure to store indices of characters or values * Using a library like Lodash, which provides a function called `lastIndexOf()` that can be used instead of the standard JavaScript method. In summary, the benchmark compares two approaches for finding the last occurrence of a character in a string: traditional `lastIndexOf()` and splitting into an array using `split+pop`. The choice of approach depends on the specific requirements and performance considerations.
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Split Pop vs Slice lastIndexOf
Performance Test: substring vs split pop
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