Flipping a binary array?

Question

Flipping a binary array?

Is there a optimized method for inverting a binary array of any length? For example, changing all 1s to 0s and all 0s to 1s within the array.

var arr1 = [ 0, 0, 1, 1, 1, 0, ..., 1 ];

javascript

Answer 1

Answer №1

Opting for a binary operation is proven to be more efficient compared to other methods.

let myArray = [1, 0, 1, 0, 0, 1, 0];
for (let j = 0; j < myArray.length; j += 1) {
    myArray[j] ^= 1;
}
console.log(myArray);
# [0, 1, 0, 1, 1, 0, 1]

The concept of using Binary XOR with 2 is effective because

console.log(1 ^ 1);   // 0
console.log(0 ^ 1);   // 1

Answer 2

Opting for a binary operation is proven to be more efficient compared to other methods.

let myArray = [1, 0, 1, 0, 0, 1, 0];
for (let j = 0; j < myArray.length; j += 1) {
    myArray[j] ^= 1;
}
console.log(myArray);
# [0, 1, 0, 1, 1, 0, 1]

The concept of using Binary XOR with 2 is effective because

console.log(1 ^ 1);   // 0
console.log(0 ^ 1);   // 1

Answer 3

Answer №2

When it comes to JavaScript, focusing on "efficiency" questions can be tricky because different engines perform differently when it comes to optimization. It's often not worth the effort to optimize before you actually have a problem to solve, especially since JavaScript engines can have vastly different performance profiles.

That being said, barring any unforeseen circumstances, using a simple for loop with cached length is usually the most efficient approach.

var arr1 = [ 0, 0, 1, 1, 1, 0, ..., 1 ];
var n, l;
for (n = 0, l = arr1.length; n < l; ++n) {
    arr1[n] = arr1[n] === 0 ? 1 : 0;
}

Remember, address performance concerns only when they arise and evaluate optimizations by testing in your target environments (either within your application or using tools like http://jsperf.com).

Answer 4

When it comes to JavaScript, focusing on "efficiency" questions can be tricky because different engines perform differently when it comes to optimization. It's often not worth the effort to optimize before you actually have a problem to solve, especially since JavaScript engines can have vastly different performance profiles.

That being said, barring any unforeseen circumstances, using a simple for loop with cached length is usually the most efficient approach.

var arr1 = [ 0, 0, 1, 1, 1, 0, ..., 1 ];
var n, l;
for (n = 0, l = arr1.length; n < l; ++n) {
    arr1[n] = arr1[n] === 0 ? 1 : 0;
}

Remember, address performance concerns only when they arise and evaluate optimizations by testing in your target environments (either within your application or using tools like http://jsperf.com).

Answer 5

Answer №3

To easily manipulate the array, iterate over it and assign 1 for 0 and 0 for all other values.

var newArr = originalArr.map(function(element) { return element === 0 ? 1 : 0; })

FIDDLE

Answer 6

To easily manipulate the array, iterate over it and assign 1 for 0 and 0 for all other values.

var newArr = originalArr.map(function(element) { return element === 0 ? 1 : 0; })

FIDDLE

Answer 7

Answer №4

Although not the most efficient method, this is a creative approach to solving the issue.

var arr1 = [ 0, 0, 1, 1, 1, 0, 1 ];
var reversed = JSON.parse(JSON.stringify(arr1).replace(/[01]/g, function(x){ return x==0?1:0;}));

Converts array into a string
Uses regular expression to switch characters in the string
Converts the modified string back into an array

Expanded into separate lines:

var arr1 = [ 0, 0, 1, 1, 1, 0, 1 ];
var arrayString = JSON.stringify(arr1);
var reverse1and0 = arrayString.replace(/[01]/g, function(x){ return x==0?1:0;});
var reversedArray =  JSON.parse(reverse1and0);

Answer 8

Although not the most efficient method, this is a creative approach to solving the issue.

var arr1 = [ 0, 0, 1, 1, 1, 0, 1 ];
var reversed = JSON.parse(JSON.stringify(arr1).replace(/[01]/g, function(x){ return x==0?1:0;}));

Converts array into a string
Uses regular expression to switch characters in the string
Converts the modified string back into an array

Expanded into separate lines:

var arr1 = [ 0, 0, 1, 1, 1, 0, 1 ];
var arrayString = JSON.stringify(arr1);
var reverse1and0 = arrayString.replace(/[01]/g, function(x){ return x==0?1:0;});
var reversedArray =  JSON.parse(reverse1and0);

Answer 9

Answer №5

If you want to experiment with a for loop, here's some code you can try out.

Example:

var arr1 = [0, 0, 1, 1, 1, 0, 1];

for (var i = 0; i < arr1.length; i++) {
    arr1[i] = 1 - arr1[i]
}

To see how this binary operation performs, check out: http://jsperf.com/test-foor-loop

Here's a demo for you to play around with: http://jsfiddle.net/IrvinDominin/Kw3e6/

Answer 10

If you want to experiment with a for loop, here's some code you can try out.

Example:

var arr1 = [0, 0, 1, 1, 1, 0, 1];

for (var i = 0; i < arr1.length; i++) {
    arr1[i] = 1 - arr1[i]
}

To see how this binary operation performs, check out: http://jsperf.com/test-foor-loop

Here's a demo for you to play around with: http://jsfiddle.net/IrvinDominin/Kw3e6/

Answer 11

Answer №6

It appears that this has evolved into a competition, so why not consider utilizing Typed Arrays for optimization?

// Create an array with a length of 1024
var length = 1024;
var arr = [];
for (var i = 0; i < length; i++) {
  arr.push(Math.random() > 0.5 ? 1 : 0);
}

var typedLoop = function() {
  var typed = new Uint8Array(arr);
  for (var i = 0; i < typed.length; i++) {
    typed[i] = (typed[i] == 0 ? 1 : 0);
  }
  return arr;
}

var untypedLoop = function() {
  for (var i = 0; i < arr.length; i++) {
    arr[i] = (arr[i] == 0 ? 1 : 0);
  }
  return arr;
}


var withClosure = function() {
  return arr.map(function(x) { return x === 0 ? 1 : 0; });
}

// Measuring elapsed time with numerous repetitions
var reps = 10000;

var time = function(f) {
  var before = new Date().getTime();
  for(var i = 0; i < reps; i++) {
    f();
  }
  console.log(new Date().getTime() - before);
}

Here are some results:

time(typedLoop)
212

time(untypedLoop)
6169

time(withClosure)
601

I find this comparison quite intriguing. Utilizing a typed array is the most efficient in terms of performance. Contrarily, using closures with a regular array takes three times longer. A standard for loop implementation is 30 times slower. These results are specific to my current environment and setup.

Note that measuring efficiency solely based on elapsed time may not provide a comprehensive assessment but can give a practical indication.

In real-world scenarios, these differences may not be significant as you may not frequently calculate long arrays thousands of times. Opt for clarity in your code rather than purely focusing on speed. Efficiency isn't always synonymous with the best approach.

Answer 12

It appears that this has evolved into a competition, so why not consider utilizing Typed Arrays for optimization?

// Create an array with a length of 1024
var length = 1024;
var arr = [];
for (var i = 0; i < length; i++) {
  arr.push(Math.random() > 0.5 ? 1 : 0);
}

var typedLoop = function() {
  var typed = new Uint8Array(arr);
  for (var i = 0; i < typed.length; i++) {
    typed[i] = (typed[i] == 0 ? 1 : 0);
  }
  return arr;
}

var untypedLoop = function() {
  for (var i = 0; i < arr.length; i++) {
    arr[i] = (arr[i] == 0 ? 1 : 0);
  }
  return arr;
}


var withClosure = function() {
  return arr.map(function(x) { return x === 0 ? 1 : 0; });
}

// Measuring elapsed time with numerous repetitions
var reps = 10000;

var time = function(f) {
  var before = new Date().getTime();
  for(var i = 0; i < reps; i++) {
    f();
  }
  console.log(new Date().getTime() - before);
}

Here are some results:

time(typedLoop)
212

time(untypedLoop)
6169

time(withClosure)
601

I find this comparison quite intriguing. Utilizing a typed array is the most efficient in terms of performance. Contrarily, using closures with a regular array takes three times longer. A standard for loop implementation is 30 times slower. These results are specific to my current environment and setup.

Note that measuring efficiency solely based on elapsed time may not provide a comprehensive assessment but can give a practical indication.

In real-world scenarios, these differences may not be significant as you may not frequently calculate long arrays thousands of times. Opt for clarity in your code rather than purely focusing on speed. Efficiency isn't always synonymous with the best approach.

Flipping a binary array?

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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