CODEWITHSUNDEEP
javascriptfor-loopwhile-loopslice
num1prospect
num1prospect

Reputation: 13

javascript slice within loop for array

I want to take an array output like the following:

 [a,
  b,
  c,
  d,
  e,
  f]

and slice it into sections, then output each new array on a newline like this: 

 [a,b
  c,d
  e,f]

Here's what i have so far: 

var data = "";
for (i = 0; i < 4; i+=2) {
data += output.slice(i,2);

}
return data;

I've been working at this for some time now trying different things to make this work but no luck. I'm new to JS, so i need some help.

Upvotes: 0

Views: 3279

Answers (4)

Burak
Burak

Reputation: 83

While zos0K's answer should suffice for slicing, one point I would like to mention is that if you just want to output the string and do nothing else with the resulting sliced arrays, I would recommend that you directly add them to a string and then print it out as aposed to creating a new array for every couple strings. While it does the job, Array.prototype.slice returns a new array each time, and creating new arrays can get expensive fairly quickly.

Upvotes: 1

Ele
Ele

Reputation: 33726

Assuming they are only chars (1 char) and there are not empty chars, you can join, match the chars as pairs using the regex /(.+?){2}/g, map to char,char and finally join with \n.

let output = ['a', 'b', 'c', 'd', 'e', 'f'],
    data = output.
           join('').
           match(/(.+?){2}/g).
           map(s => s.split('').join(',')).join('\n');


console.log(data);

Upvotes: 1

gotnull
gotnull

Reputation: 27214

let data = ['a', 'b', 'c', 'd', 'e', 'f']
    
var output = "";
for (i = 0; i < data.length; i+=2) { 
    output += data.slice(i, i+2).join(",") + "\n";
}
console.log(`[${output.substring(0, output.lastIndexOf("\n"))}]`);

Upvotes: 1

Mark
Mark

Reputation: 92440

Since you have six elements in your array, you need to iterate to 6 not 4. The best way to do that is to use the length of your array, so if the length changes you don't need to change the loop. When taking a slice you also want slice(i, i+2)

If you just want to make a string, you can add a \n character in each iteration:

let output = ['a', 'b', 'c', 'd', 'e', 'f']

var data = "";
for (i = 0; i < output.length; i+=2) { 
    data += output.slice(i,i+2).join(" ") + "\n";
}
console.log(data);

Upvotes: 3

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