Swapping consecutive/adjacent characters of a string in JavaScript

user_4336593 0
Viewed 528

Example string: astnbodei, the actual string must be santobedi. Here, my system starts reading a pair of two characters from the left side of a string, LSB first and then the MSB of the character pair. Therefore, santobedi is received as astnbodei. The strings can be a combination of letters and numbers and even/odd lengths of characters.

My attempt so far:

var attributes_ = [Name, Code,
    Firmware, Serial_Number, Label
]; //the elements of 'attributes' are the strings
var attributes = [];

for (var i = 0; i < attributes_.length; i++) {
    attributes.push(swap(attributes_[i].replace(/\0/g, '').split('')));
}

function swap(array_attributes) {
    var tmpArr = array_attributes;
    for (var k = 0; k < tmpArr.length; k += 2) {
        do {
            var tmp = tmpArr[k];
            tmpArr[k] = tmpArr[k+1]
            tmpArr[k+1] = tmp;
        } while (tmpArr[k + 2] != null);
    }
    return tmpArr;
}

msg.Name = attributes; //its to check the code

return {msg: msg, metadata: metadata,msgType: msgType}; //its the part of system code

While running above code snippet, I received the following error:

Can't compile script: javax.script.ScriptException: :36:14 Expected : but found ( return {__if(); ^ in at line number 36 at column number 14

I'm not sure what the error says. Is my approach correct? Is there a direct way to do it?

swap arrays algorithm javascript string
4 Answers

Did you try going through the array in pairs and swapping using ES6 syntax?

You can swap variables like this in ES6: [a, b] = [b, a]

user_161421970

Below is one way to do it. The code you have is not valid because return is not allowed outside a function.

let string = "astnbodei";
let myArray = string.split('');
let outputArray = [];

for (i=0; i<myArray.length; i=i+2) {
    outputArray.push(myArray[i+1]);
  outputArray.push(myArray[i]);
}

console.log(outputArray.join(''));

user_59338220

Consecutive pairwise character swapping of/within a string very easily can be solved by a reduce task ...

function swapCharsPairwise(value) {
  return String(value)
    .split('')
    .reduce((result, antecedent, idx, arr) => {
      if (idx % 2 === 0) {

        // access the Adjacent (the Antecedent's next following char).
        adjacent = arr[idx + 1];

        // aggregate result while swapping `antecedent` and `adjacent`.
        result.push(adjacent, antecedent);
      }
      return result;
    }, []).join('');
}
console.log(
  'swapCharsPairwise("astnbodei") ...',
  swapCharsPairwise("astnbodei")
);

user_26272430

The reason for the error in the question was the placement of the function swap. However, switching its placement gave me another error:

java.util.concurrent.ExecutionException: java.util.concurrent.ExecutionException: javax.script.ScriptException: delight.nashornsandbox.exceptions.ScriptCPUAbuseException: Script used more than the allowed [8000 ms] of CPU time.

@dikuw's answer helped me partially. The following line of code worked for me:

var attributes_ = [Name, Code,
    Firmware, Serial_Number, Label
]; //the elements of 'attributes' are the strings
var attributes = [];

for (var i = 0; i < attributes_.length; i++) {
    attributes.push(swap(attributes_[i].replace(/\0/g, '').split('')));
}

return {msg: msg, metadata: metadata,msgType: msgType};

function swap(array_attributes) {
    var tmpArr = [];
    for (var k = 0; k < array_attributes.length; k= k+2) {
        if( (array_attributes[k + 1] != null)) {
            tmpArr.push(array_attributes[k+1]);
            tmpArr.push(array_attributes[k]);
    }}
    return tmpArr.join('');
}
user_43365930
Related