Benchmark: count number of chars in a string 2

Tests:

regex
("this is foo bar".match(/o/g)||[]).length
split
"this is foo bar".split("o").length-1
for loop1
var stringsearch = "o"; var str = "this is foo bar"; for(var count=-1,index=-2; index != -1; count++,index=str.indexOf(stringsearch,index+1) );
for loop 2
var stringsearch = "o"; var str = "this is foo bar"; for(var i=count=0; i<str.length; count+=+(stringsearch===str[i++]));
deleting
var str = "this is foo bar"; str.length - str.replace(/o/g,'').length;
histogram
var str = "this is foo bar"; var schar = 'o'; var hist={}; for(si in str){ hist[str[si]] = hist[str[si]] ? 1+hist[str[si]]:1; }
for in
var str = "this is foo bar"; var char = 'o'; var count = 0; for (let c in str) { if (str[c] === char) count++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
regex
split
for loop1
for loop 2
deleting
histogram
for in

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

Browser/OS: Chrome 79 on Linux

View result in a separate tab

Test name	Executions per second
regex	4693308.0 Ops/sec
split	6017223.0 Ops/sec
for loop1	11054253.0 Ops/sec
for loop 2	187614.0 Ops/sec
deleting	5546296.5 Ops/sec
histogram	68407.8 Ops/sec
for in	209206.4 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The benchmark is defined by a JSON object with several properties:

* `Name`: a unique name for the benchmark
* `Description`: an optional description of the benchmark (not filled in this case)
* `Script Preparation Code` and `Html Preparation Code`: optional code that can be executed before running the benchmark (also not filled in this case)

**Individual Test Cases**

The benchmark consists of six test cases, each with a unique `Benchmark Definition`:

1. **Regex**: `(\"this is foo bar\".match(/o/g)||[]).length`
2. **Split**: `"this is foo bar".split("o").length-1`
3. **For Loop 1**: A manual loop that searches for the character "o" in a string using `indexOf()`.
4. **For Loop 2**: Similar to For Loop 1, but uses a more concise syntax with conditional increment.
5. **Deleting**: `str.length - str.replace(/o/g,'').length`
6. **Histogram**: A manual loop that creates a histogram of character frequencies in a string.

**Comparing Approaches**

The test cases compare different approaches to counting the number of occurrences of a specific character ("o") in a string:

* **Regex**: Uses regular expressions to find all occurrences of "o" and returns the length of the match array.
* **Split**: Splits the string into substrings using "o" as the delimiter, counts the number of substrings excluding the empty one (i.e., the last character "o"), and subtracts this from the original string length to get the count.
* **For Loop 1** and **2**: Manual loops that use `indexOf()` or conditional increment to find the character "o" in a string, respectively. These approaches have varying levels of efficiency due to their implementation details (e.g., loop overhead, branch prediction).
* **Deleting**: Uses `replace()` to remove all occurrences of "o" from the string and then subtracts the length of the resulting string from the original string length to get the count.
* **Histogram**: Creates a histogram by counting the frequency of each character in the string and returns the total number of occurrences of "o".

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* **Regex**: Pros: concise, efficient, and widely supported. Cons: can be slow for very large strings due to the overhead of regular expression engines.
* **Split**: Pros: simple, fast, and easy to understand. Cons: may not work well for non-delimited strings or characters that appear multiple times in a row.
* **For Loop 1** and **2**: Pros: flexible, can be optimized for performance. Cons: manual implementation can lead to errors and is less concise than other approaches.
* **Deleting**: Pros: simple, fast. Cons: assumes that removing all occurrences of "o" from the string is desirable, which may not always be the case.
* **Histogram**: Pros: accurate, comprehensive. Cons: more complex to implement and understand, especially for large strings.

**Other Alternatives**

Some alternative approaches could include:

* Using `Array.prototype.filter()` or `Array.prototype.every()` to create an array of indices where the character "o" appears, and then returning the length of this array.
* Utilizing JavaScript's built-in string methods, such as `String.prototype.search()` or `String.prototype.lastIndexOf()`, to find the first or last occurrence of "o".
* Leveraging native optimization techniques, like loop unrolling or SIMD instructions, to improve performance.

Keep in mind that these alternatives may have varying levels of complexity and overhead compared to the existing test cases.

Related benchmarks:

count number of chars in a string 2 (version: 0)

Comparing performance of: regex vs split vs for loop1 vs for loop 2 vs deleting vs histogram vs for in

Created: 4 years ago by: Guest

Jump to the latest result

regex

split

for loop1

for loop 2

deleting

histogram

for in

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):