How to return the array without the brackets javascript [duplicate]

Question

So I have this code where I have an array of sentences which are being prompted through a switch where the user is to ask how many sentences they want to display 1 - 5. it will then loop through and randomly display the number of sentences requested from the array.

var sentences = ["sentence one", "sentence two", "sentence three",
  "sentence 4", "sentence 5"];

function shuffle(a) {
  for (i = a.length - 1; i; i--) {
    let j = Math.floor(Math.random() * i);
    [a[i - 1], a[j]] = [a[j], a[i - 1]];
  }
}

var random = prompt("how many sentences do you want?");
switch (random) {
  case "1":
    shuffle(sentences)
    console.log(sentences(0, 1));
    break;

  case "2":
    shuffle(sentences)
    console.log(sentences.slice(0, 2))
    break;

  case "3":
    shuffle(sentences)
    console.log(sentences.slice(0, 3))
    break;

  case "4":
    shuffle(sentences)
    console.log(sentences.slice(0, 4))
    break;

  case "5":
    shuffle(sentences)
    console.log(sentences.slice(0, 5))
    break;

  default:
    console.log("incorrect number");
}

The code works fine, but when it returns, it displays the array of course: say if the person wanted 3 sentences:

(3) ["sentence two", "sentence four", "sentence five"]

I want to return the sentences itself and not the array so:

sentence two, sentence four, sentence five

I tried converting to a string with .length but this then returns the number of characters in the string eg prompt entered was 5 so it returns:

sente

Anyone have any ideas, much appreciated :)

It's important to note first of all that your code isn't actually returning anything; it's just logging a representation of your array to the console — Hamms
– Hamms, Commented Mar 27, 2018 at 0:40
If you want to log a prettier representation of your array, one good option is array.join — Hamms
– Hamms, Commented Mar 27, 2018 at 0:40
Use .slice to strip the brackets before you display it. w3schools.com/jsref/jsref_slice_array.asp w3schools.com/jsref/jsref_slice_string.asp Or alternatively you can use split: w3schools.com/jsref/jsref_split.asp OR you can use replace: w3schools.com/jsref/jsref_replace.asp — user8557879
– user8557879, Commented Mar 27, 2018 at 0:41
.slice() always returns an Array. If you're outputting to HTML you can just assign the Array to the Element.innerHTML or Element.value and it gives you a String without [] anyways. — StackSlave
– StackSlave, Commented Mar 27, 2018 at 0:43
Why are you using switch/case? Just sentences.slice(0, random) — Barmar
– Barmar, Commented Mar 27, 2018 at 0:48

Josh McMillan · Accepted Answer · 2018-03-27 00:42:18Z

3

You can do this by "joining" your array with the join method. For example, given an array of ["foo", "bar"], calling ["foo", "bar"].join(", ") will output a string containing foo, bar.

Here's an example:

> var foo = ['bar', 'bat'];
[ 'bar', 'bat' ]
> foo.join(', ');
'bar, bat'

answered Mar 27, 2018 at 0:42

Josh McMillan

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Comments

Mario L · Accepted Answer · 2018-03-27 00:51:47Z

0

You can use join (). The join() method joins all elements of an array (or an array-like object) into a string and returns this string.

In your code:

 console.log((sentences.slice(0, 3)).join(', '));

answered Mar 27, 2018 at 0:51

Mario L

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Comments

Sébastien · Accepted Answer · 2018-03-27 00:47:31Z

Use join() to concatenate all the values from the array with a string (like ', ')

var sentences = ["sentence one", "sentence two", "sentence three",
  "sentence 4", "sentence 5"];

function shuffle(a) {
  for (i = a.length - 1; i; i--) {
    let j = Math.floor(Math.random() * i);
    [a[i - 1], a[j]] = [a[j], a[i - 1]];
  }
}

var random = prompt("how many sentences do you want?");

shuffle(sentences);

switch (random) {
  case "1":
    sentences = sentences.slice(0, 1);
    break;

  case "2":
    sentences = sentences.slice(0, 2);
    break;

  case "3":
    sentences = sentences.slice(0, 3);
    break;

  case "4":
    sentences = sentences.slice(0, 4)
    break;

  case "5":
    sentences = sentences.slice(0, 5);
    break;

  default:
    console.log("incorrect number");
}

console.log(sentences.join(', '));

Eric · Accepted Answer · 2018-03-27 00:50:37Z

To achieve what you want, you can use the spread ... operator in ES6.

var sentences = ["sentence one", "sentence two", "sentence three", 
"sentence 4", "sentence 5"];

  function shuffle(a) {
        for (i = a.length - 1; i; i--) {
            let j = Math.floor(Math.random() * i);
            [a[i - 1], a[j]] = [a[j], a[i - 1]];
        }
    }

 var random = prompt("how many sentences do you want?");
  switch (random) {
    case "1":
    shuffle(sentences)
   console.log(...sentences(0, 1));
      break;

      case "2":
       shuffle(sentences)
      console.log(...sentences.slice(0, 2))
      break;

      case "3":
       shuffle(sentences)
      console.log(...sentences.slice(0, 3))
      break;

      case "4":
       shuffle(sentences)
      console.log(...sentences.slice(0, 4))
      break;

      case "5":
       shuffle(sentences)
      console.log(...sentences.slice(0, 5))
      break;

      default:
      console.log("incorrect number");
}

As a side note, the switch statement is repetitive and unnecessary:

 var random = +prompt("how many sentences do you want?");
 if (0 <= random <= 5) {
   shuffle(sentences);
   console.log(...sentences.slice(0, random));
 } else {
   console.log("invalid number");
 }

Here, + casts the number string to a number. You can also explicitly cast using Number(prompt(..)).

EDIT: I see that now you want to insert comma between elements.

You can use Array.prototype.join.

 var random = +prompt("how many sentences do you want?");
 if (0 <= random <= 5) {
   shuffle(sentences);
   console.log(sentences.slice(0, random).join(', ');
 } else {
   console.log("invalid number");
 }

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