How to remove specific part of string from each item of array using javascript?

Question

Given the following:

var arr = [
    "one,two,three",
    "four,five,six,seven",
    "eight,nine,ten",
    "11,12,13,14"
];

What's the best way to remove the second word from each element in the array? The desired output of the array would be:

arr = [
    "one,three",
    "four,six,seven",
    "eight,ten",
    "11,13,14"
];

I felt the most logical approach would be to use a for loop to cycle through the array and remove index 1 from each element, like as follows:

for(var i=0; i < arr.length; i++) {
    i.splice(1,1).join(';');
}

(within the loop, I also tried arr[i].splice(1,1).join(';');) --- but neither approach is returning the desired outcome. What am I doing wrong and what's the most efficient way to do this?

do you want the output to be an array with the removed elements, right? — blurfus
– blurfus, Commented Sep 21, 2016 at 17:49

Pranav C Balan · Accepted Answer · 2016-09-21 17:59:53Z

4

You need to split the array first and then remove the element.

var arr = [
  "one,two,three",
  "four,five,six,seven",
  "eight,nine,ten",
  "11,12,13,14"
];

for (var i = 0; i < arr.length; i++) {
  // split the string based on ,
  var a = arr[i].split(',');
  // remove second element from string
  a.splice(1, 1);
  // join the updated string array
  arr[i] = a.join();
}

console.log(arr);

Or another method using String#indexOf and String#slice methods.

var arr = [
  "one,two,three",
  "four,five,six,seven",
  "eight,nine,ten",
  "11,12,13,14"
];

for (var i = 0; i < arr.length; i++) {
  // get the index of first ,
  var index = arr[i].indexOf(','),
    // get the index of second index
    index1 = arr[i].indexOf(',', index + 1);
  // generate the string based on index
  arr[i] = arr[i].slice(0, index) + arr[i].slice(index1);
}

console.log(arr);

edited Sep 21, 2016 at 17:59

answered Sep 21, 2016 at 17:51

Pranav C Balan

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Comments

SparK · Accepted Answer · 2016-09-21 17:53:41Z

0

Firstly you must break your strings in arrays so:

elements = arr[i].split(',');

then you splice the second element and join the string back:

elements.splice(1,1)
result = elements.join(',');

lastly you replace the string with the new one:

arrs[i] = result

To wrap up:

for(var i=0; i<arr.length; i++){
    elements = arrs[i].split(',');
    elements.splice(1,1);
    arrs[i] = elements.join(',');
}

Have fun!

answered Sep 21, 2016 at 17:53

SparK

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Comments

Mr. Polywhirl · Accepted Answer · 2016-09-21 18:00:05Z

0

The Array.prototype.splice function returns the removed items(s).

You need to store the array, remove the items(s), and finally return the array.

var arr = [
  "one,two,three",
  "four,five,six,seven",
  "eight,nine,ten",
  "11,12,13,14"
];

function spliceWords(arr, pos, length) {
  length = length || 1; // Default number to remove is 1.
  return arr.map(function(item) {
    var words = item.split(',');
    words.splice(pos, length); // Splice removes the items in-place.
    return words.join(',');
  });
}

var arr2 = spliceWords(arr, 1);

document.body.innerHTML = JSON.stringify(arr2, null, 4);

body { font-family:monospace; white-space:pre; }

edited Sep 21, 2016 at 18:00

answered Sep 21, 2016 at 17:54

Mr. Polywhirl

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Comments

Mohammad · Accepted Answer · 2016-09-21 18:00:42Z

0

You can use .map() to changing every item of array, and use .replace() to removing second value from string.

var arr = [
    "one,two,three",
    "four,five,six,seven",
    "eight,nine,ten",
    "11,12,13,14"
];

arr = arr.map(function(val){
    return val.replace(/([\w]+),[\w]+,(.*)/, "$1,$2");
});
console.log(arr);

answered Sep 21, 2016 at 18:00

Mohammad

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Comments

Nina Scholz · Accepted Answer · 2016-09-21 18:09:24Z

0

You could use regular expression for the string, which looks for a comma, any character, non gready and for another comma, which is not included for replacing.

var arr = ["one,two,three", "four,five,six,seven", "eight,nine,ten", "11,12,13,14"];

arr = arr.map(function (a) {
    return a.replace(/,.*?(?=,)/, '');
});

console.log(arr);

edited Sep 21, 2016 at 18:09

answered Sep 21, 2016 at 17:53

Nina Scholz

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Comments

Chandru Krishnar · Accepted Answer · 2016-09-21 18:29:02Z

0

Loop through each element in array
Use the split() method to create array of comma separated element
use splice() method to remove 2nd part in the array

Here is the algorithm:

for(var i=0; i < arr.length; i++) {  
var a = arr[i].split(",");  
a.splice(1,1);  
arr[i] = a.join();  
}

answered Sep 21, 2016 at 18:29

Chandru Krishnar

11 bronze badge

Comments

R. Schifini · Accepted Answer · 2016-09-22 04:14:08Z

0

Here you go:

arr.map(x => x.replace(x.match(/,[^,]*/),""))

Or

arr.map(function(x) x.replace(x.match(/,[^,]*/),""))

Result:

["one,three", "four,six,seven", "eight,ten", "11,13,14"]

The regular expression looks for the first comma (,) and grabs everything that follows that is not a comma ([^,]*). This part of the string will be replaced by nothing ("").

The map method will apply this function to every element of the array.

edited Sep 22, 2016 at 4:14

answered Sep 21, 2016 at 17:54

R. Schifini

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