Javascript build a string from the length of an array of ?,

Question

Is there a pretty way of building a string of something like (?,?,?) for the number of items in an array

I've tried

values.map(() => '?,')
values.reduce((a,b) => {a + '?,'},'')

but both are not working

Nina Scholz · Accepted Answer · 2018-07-31 08:20:27Z

2

You could map question marks for each element and join the array in an template literal.

var array = [1, 2, 3],
    string = `(${array.map(_ => '?').join()})`;
    
console.log(string);

answered Jul 31, 2018 at 8:15

Nina Scholz

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Comments

Jonas Wilms · Accepted Answer · 2018-07-31 08:15:39Z

1

  "(" + values.map(el => "?").join() + ")"

You could just join them.

answered Jul 31, 2018 at 8:15

Jonas Wilms

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Amit Chauhan · Accepted Answer · 2018-07-31 08:16:49Z

0

You need to return from map and reduce functions.

var valuse = [1,2,3]
var newValues = values.reduce((a,b) => a === '' ? '?' : a + ',?','');
console.log(newValues);

answered Jul 31, 2018 at 8:16

Amit Chauhan

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Bargros · Accepted Answer · 2018-07-31 08:43:11Z

0

You could simply use the arrays forEach() extension, like this:

var string = "";
[1,2,3,4,5,6,7,8,9].forEach((elem, index) => string += "?");

answered Jul 31, 2018 at 8:43

Bargros

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