Benchmark: count number of chars in a string

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; }

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

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested.

**Benchmark Overview**

The benchmark is designed to measure the performance of different JavaScript operations on a given string input. The test cases are:

1. Counting the number of characters in a string using regular expressions (`regex`)
2. Splitting a string into an array using the `split()` method (`split`)
3. Searching for a substring within a string using a `for` loop (`for loop 1`)
4. Searching for a substring within a string using another `for` loop with a different approach (`for loop 2`)
5. Removing characters from a string using the `replace()` method (`deleting`)
6. Creating a histogram of character frequencies in a string (`histogram`)

**Options Compared**

The benchmark compares the performance of different approaches for each operation:

* Regular expressions (`regex`) vs. simple string iteration (`for loop 1` and `for loop 2`)
* Splitting a string into an array using `split()` vs. removing characters from the original string (`deleting`)
* Using a `histogram` data structure to count character frequencies vs. using a simple `for` loop with incremental indexing (`for loop 1`)

**Pros and Cons of Each Approach**

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

* **Regular expressions (regex)**:
	+ Pros: Can be used for more complex matching patterns, allows for regular expression flags for optimization.
	+ Cons: Can be slower due to the complexity of the regular expression engine, may not be suitable for very large strings.
* **Simple string iteration (for loop 1 and 2)**:
	+ Pros: Generally faster than using `regex` or `split()`, can be optimized with incremental indexing.
	+ Cons: May require more code and maintenance due to the need for manual indexing, limited flexibility for complex matching patterns.
* **Splitting a string into an array (split())**:
	+ Pros: Simple and straightforward, suitable for most use cases.
	+ Cons: May not be as efficient as simple string iteration, can lead to extra memory allocation and copying of characters.
* **Removing characters from a string (deleting)**:
	+ Pros: Similar performance characteristics to `split()`, allows for more flexibility in string manipulation.
	+ Cons: May allocate extra memory to store the resulting string, can be slower than simple string iteration if using a large character set.
* **Histogram data structure**:
	+ Pros: Allows for efficient counting of character frequencies, suitable for large strings.
	+ Cons: Requires additional memory allocation and copying of characters, may not be as straightforward to implement.

**Libraries Used**

The benchmark uses the following JavaScript library:

* No external libraries are explicitly mentioned in the provided code snippets. However, it's likely that the benchmark is using a modern JavaScript engine or runtime environment that provides optimized implementations for these operations.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax used in this benchmark beyond the standard `for` loops and `regex` expressions. The focus is on comparing different approaches to performance, rather than demonstrating new or experimental features.

Overall, this benchmark provides a useful comparison of different approaches for common string operations in JavaScript, allowing users to choose the most efficient method for their specific use case.

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	4949697.0 Ops/sec
split	6180327.5 Ops/sec
for loop1	10303806.0 Ops/sec
for loop 2	185075.1 Ops/sec
deleting	5308489.5 Ops/sec
histogram	68482.1 Ops/sec

Related benchmarks:

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

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

Created: 4 years ago by: Guest

Jump to the latest result

regex

split

for loop1

for loop 2

deleting

histogram

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):