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pop() vs shift()
(version: 1)
Comparing performance of:
pop vs shift
Created:
one year ago
by:
Guest
Go to the latest result
Script Preparation code:
var array = []; for(var i = 0; i < 100000; i++){array.push(Math.random());}
Tests:
pop
while (array.length > 0) { array.pop(); }
shift
while (array.length > 0) { array.shift(); }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
pop
shift
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
4 months ago
)
User agent:
Mozilla/5.0 (X11; Linux x86_64; rv:148.0) Gecko/20100101 Firefox/148.0
Browser/OS:
Firefox 148 on Linux
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=627055" width="100%" height="500px"></iframe>
shift
1591.6M/s
pop
638.2M/s
View exact numbers
Test name
Executions per second
✓
shift
1,591,614,720 Ops/sec
pop
638,205,312 Ops/sec
Autogenerated LLM Summary
(model
gpt-4o-mini
, generated one year ago):
The provided JSON benchmark focuses on comparing the performance of two array manipulation methods in JavaScript: `pop()` and `shift()`. Here’s a detailed explanation of what is being tested, the options compared, and their respective pros and cons. ### Benchmark Overview - **Benchmark Name**: `pop() vs shift()` - **Setup**: The benchmark initializes an empty array and fills it with 100,000 random numbers using `Math.random()`. ### Test Cases 1. **pop**: - **Function**: `array.pop()` - **Behavior**: The `pop()` method removes the last element from an array and returns that element. It modifies the length of the array. - **Benchmark Definition**: It uses a `while` loop to continually remove elements until the array is empty: `while (array.length > 0) { array.pop(); }`. 2. **shift**: - **Function**: `array.shift()` - **Behavior**: The `shift()` method removes the first element from an array and returns that element. Like `pop()`, it modifies the length of the array. - **Benchmark Definition**: This also uses a `while` loop to remove elements until the array is empty: `while (array.length > 0) { array.shift(); }`. ### Performance Metrics - **Executions per Second**: - `pop()`: Approximately 69,014,224 operations per second. - `shift()`: Approximately 68,533,288 operations per second. From the benchmark results, we observe that `pop()` performs slightly better than `shift()`. ### Pros and Cons of Each Method #### pop() Method - **Pros**: - Generally faster than `shift()` since it operates on the end of the array, where no re-indexing of other elements is needed. - Commonly used in stack data structure implementations. - **Cons**: - Only useful if you need to remove elements from the end. It doesn't fit use cases where elements need to be removed from the beginning. #### shift() Method - **Pros**: - Useful for implementing queues where you often need to remove the first element in an orderly fashion. - Provides an easy and straightforward way to manipulate arrays. - **Cons**: - Slower than `pop()` because it requires re-indexing all the other elements in the array after removing the first element. This can lead to performance bottlenecks, especially for large arrays. ### Other Considerations - **Alternatives**: In scenarios where frequent removals from the start of the array are required, using data structures optimized for such operations, like linked lists, may be a better alternative. While JavaScript does not natively support linked lists, developers can implement them to gain better performance for specific use cases. - **Library Implications**: The benchmark does not utilize an external library; it relies solely on built-in JavaScript methods. This ensures that the results are consistent across different JavaScript engines since these methods are standard in the ECMAScript specification. In summary, this benchmark evaluates a fundamental aspect of array manipulation in JavaScript. It highlights the differences in performance and use cases between the `pop()` and `shift()` methods, informing developers about when to use each method based on their performance characteristics and application needs.
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