Is there an easy way to create an array of empty strings in javascript? Currently the only way I can think to do it is with a loop:
var empty = new Array(someLength);
for(var i=0;i<empty.length;i++){
empty[i] = '';
}
but I'm wondering if there is some way to do this in one line using either regular javascript or coffeescript.
Update: on newer browsers - use .fill: Array(1000).fill('') will create an array of 1000 empty strings.
Yes, there is a way:
var n = 1000;
Array(n).join(".").split("."); // now contains n empty strings.
I'd probably use the loop though, it conveys intent clearer.
function repeat(num,whatTo){
var arr = [];
for(var i=0;i<num;i++){
arr.push(whatTo);
}
return arr;
}
That way, it's perfectly clear what's being done and you can reuse it.
Array(n).join('.').split('.') also :)
split('.') fixed the off-by-one error with the original split('')You can get an array defining the size and fill it with some tokens:
const arr = Array(size).fill("");
any[] not string[]here's a simpler way using generic protos on Array and String:
"".split.call(Array(1001), ",")
EDIT: There's now even simpler ways, some of which are readable:
Array(1000).fill("");
" ".repeat(999).split(" ");
You can try to do it by this way:
let n = 1000;
var emptyStrings = [...Array(n)].map(() => '')
Using Array.from;
const n = 5;
const arr = Array.from({length: n}).map(el => "")
console.log(arr)
You could make a function out of it:
function stringArray(length) {
var arr = [];
for(var i = 0; i < length; ++i) { arr.push(''); }
return arr;
}
You could do something like this:
var someLength = 10;
var empty = Array.apply(0, Array(someLength)).map(function(){return '';});
// result: ["", "", "", "", "", "", "", "", "", ""]
Just for fun
var empty = Array.apply(null, new Array(someLength)).map(String.prototype.valueOf,"");
valueOf. Side note - new is redundant here.
String(Array([length])).split(',').map(String.prototype.valueOf,'')The easiest thing to do in CoffeeScript is to use a loop comprehension:
a = ('' for i in [0 ... someLength]) # Note: 3 dots
a = ('' for i in [1 .. someLength]) # Or 2 dots and start at 1
#...
[1..5].map(-> '')Although not widely available, once browsers start supporting EcmaScript 6 array comprehensions, you will be able to do something along the lines of:
var n = 1000;
var empty_strs = ['' for (x of new Array(n))]
Easy enough.
Array with a length of 10 items, filled with empty strings (""):
Array.from({length: 10}).map( _ => "" );
// Array(10) [ "", "", "", "", "", "", "", "", "", "" ]
Array with a length of 10 items, filled with numbers from 0 to 9:
Array.from({length: 10}).map( (_, index) => index );
// Array(10) [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ]
Array with a length of 10 items, filled with numbers from 1 to 10:
Array.from({length: 10}).map( (_, index) => index + 1 );
// Array(10) [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]
Array with a length of 10 items, filled with string containing "Chapter (1 ... 10).":
Array.from({length: 10}).map( (_, index) => `Chapter ${index + 1}.` );
// Array(10) [ "Chapter 1.", "Chapter 2.", "Chapter 3.", ... ]
(Using _ here as we don't use the value anyway.)
