CODEWITHSUNDEEP
javascript
code7004
code7004

Reputation: 120

convert String into integer in java script without using any built in functions

Is there any trick to convert string to integer in javascript without using any function and methods?

var s = "5"
console.log(typeof(s)) // out put is string 
console.log(typeof(parseInt(s))) // i want out put which is number with out using parseInt() or other functions for optimizing code.

Any help would be appreciated. Thanks in advance.

Upvotes: 5

Views: 4619

Answers (4)

anshuVersatile
anshuVersatile

Reputation: 2068

Basically if you are searching "whole logic" to convert string to int then you have to find ASCII code for each alphabet in string and then convert it to integer and make sum of all 48 to 57 are ASCII codes are for number 0 to 1. Below is example code

let parseINT = (b) => b.split("").map((e,i) => {
    let value = e.charCodeAt(0) - 48;
    return value * [...Array(((i - b.length) * -1)).keys()].reduce((a, b) => a > 0 ? (a * 10) : 1, 0);
}).reduce((a, b) => a + b, 0)

or short form will be like

let parseINT = (b) => b.split("").map((e,i) => ((e.charCodeAt(0)  <= 57 ? e.charCodeAt(0) : 48) - 48) * [...Array(((i - b.length) * -1)).keys()].reduce((a, b) => a > 0 ? (a * 10) : 1, 0)).reduce((a, b) => a + b, 0);

Upvotes: 0

manan5439
manan5439

Reputation: 958

here is a most effective way to convert string into int without using any built in function have a look at code. Thank you:)

var s = "5"
var i = s - 0
console.log(typeof(i)) // you will get a number without using any built in function... because (-) will cast string in to number

Upvotes: 5

Mamun
Mamun

Reputation: 68933

You can cast the string to number using unary plus (+). This will do nothing much beside some code optimization.

var s = "5"
s = +s;
console.log(typeof(s), s);

var s = "5.5"
s = +s;
console.log(typeof(s), s);

Upvotes: 6

Rajesh
Rajesh

Reputation: 24955

You can try using bit-wise operator s|0. This will convert value to integer. However, this will also convert floating values to integer.

var s = "5"
var y = s|0;
console.log(typeof(y), s, y);

var s = "5.5"
var y = s|0;
console.log(typeof(y), s, y);

Upvotes: 3

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