how to split a string in two strings in javascript? - Stack Overflow

I have a string with a lot of characters. I would like to split the string into 2 sub-strings. I don't need to use getfirsthalf() and getsecondhalf(), but that is the idea of what i need to achieve.

var pleet = "This is the string with a lot of characters";

var part1 = pleet.getFirstHalf();
var part2 = pleet.getSecondHalf()

//output 
var part1 = "This is the string wi";
var part2 = "th a lot of characters";

I have a string with a lot of characters. I would like to split the string into 2 sub-strings. I don't need to use getfirsthalf() and getsecondhalf(), but that is the idea of what i need to achieve.

var pleet = "This is the string with a lot of characters";

var part1 = pleet.getFirstHalf();
var part2 = pleet.getSecondHalf()

//output 
var part1 = "This is the string wi";
var part2 = "th a lot of characters";

• javascript
• string

Share Improve this question Follow edited Sep 1, 2015 at 7:52 Tushar 87.3k2121 gold badges163163 silver badges181181 bronze badges asked Jul 31, 2015 at 11:03 user3432681user3432681 66444 gold badges1212 silver badges2727 bronze badges 3

• what effort have you made? – Daniel A. White Commented Jul 31, 2015 at 11:04
• 1 What defines 'half' of a string? – BenM Commented Jul 31, 2015 at 11:04
• @DontVoteMeDown What if the string has 7 characters? – BenM Commented Jul 31, 2015 at 11:10

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4 Answers 4

Sorted by: Reset to default 4

You can use substring() with the length of the string to divide the string in two parts by using the index.

The substring() method returns a subset of a string between one index and another, or through the end of the string.

var pleet = "This is the string with a lot of characters";
var len = pleet.length;


var firstHalf = pleet.substring(0, len / 2);
var secondHalf = pleet.substring(len / 2);

document.write(firstHalf);
document.write('<br />');
document.write(secondHalf);

You can also use substr()

You must to be more specific in your questions. But here you are a simply solution:

var str = "an string so long with the characters you need";
var strLength = str.length;
console.log(str.substring(0 , (strLength / 2));
console.log(str.substring((strLength / 2));

Assuming that when you say 'half' a string, you actually mean that two separate strings are returned containing half of the original string's characters each, you could write a prototype function to handle that as follows:

String.prototype.splitInHalf = function()
{
    var len = this.length,
        first = Math.ceil( len / 2 );

    return [
        this.substring(0, first),
        this.substring(first)
    ];
}

When called as pleet.splitInHalf(), This function will return an array containing the two halves, as follows:

["This is the string wit", "h a lot of characters"]

Since we use Math.ceil() here, the prototype will also favour the first half of the string. For example, given a string that has an odd number of characters, such as This is, the returned array will contain 4 characters in the first string, and 3 in the second, as follows:

["This", " is"]

jsFiddle Demo

Here is class example:

class strSplitterHelper {
    constructor(str) {
        this.str = str;
        this.strLength = str.length;
    }

    devide() {
        const position = this.getNearestSpace();

        if (position === null) {
            return [this.str, null];
        }

        return [
            this.str.substr(0, position),
            this.str.substr(position + 1)
        ];
    }

    getNearestSpace() {
        const middle = Math.floor(this.strLength / 2);

        for (let i = middle; i >= 0; i--) {
            if (this.str.charAt(i) === ' ') {
                return i;
            }

            if (this.str.charAt(this.strLength - i) === ' ') {
                return this.strLength - i;
            }
        }

        return null;
    }
}

const parts = new strSplitterHelper(
    'This is the string with a lot of characters'
).devide();

that will return 2 elements array.