How to increment a float by lowest zero

Question

I have a float x that can be any size and need to increment its amount by 1 on the last zero, so .1 for 1.0, .01 for 2.00, etc.

The following code works for certain numbers, but not all:

Javascript

let a = "0".repeat(floatNumber.length-2)+'1';
let position = floatNumber.indexOf(".");
let add = [a.slice(0, position), ".", a.slice(position)].join('');

1.1 becomes 1.2.

but

10.1 becomes 10.20. I need an output of 10.2.

`jquery` and `math` tags? [Really?](https://i.stack.imgur.com/ssRUr.gif) — VLAZ, Jul 01 '19 at 05:05
@VLAZ It has nothing to do with jQuery, but math seems appropriate. — JLRishe, Jul 01 '19 at 05:07
I still don't get it, `increment its amount by 1 on the last zero` then `.1 for 1.0` and `.01 for 2.00` and `10.1 becomes 10.2` seem to me like 3 different things. so which one is it? — Thomas, Jul 01 '19 at 05:11
@JonasWilms so in other words, when there is a dot, you simply append the digit `"1"` to the number? That doesn't sound right. My issue here is, what is the difference between `2`, `2.0`, `2.00` and for example `0000002` or `2.000000`? mathematically they are all the same value/float so what is the last zero in these? If `2.00` is supposed to be incremented by `0.01` then why is `10.1` not incremented by `1.0` as there is the last `0` I can see? Or by `0.01` as this would be the first zero at the end. Why is it supposed to be `10.2`? I don't get the rules. — Thomas, Jul 01 '19 at 05:35
Dood's answer is exactly what i needed. @VLAZ; sorry my first post on stackoverflow, added jquery tag as i am using the library in the program anyway. — matt, Jul 01 '19 at 07:00

score 1 · Answer 1 · answered Jul 01 '19 at 05:25

1

You could just take + increase the last digit:

    const result = input.slice(0, -1) + (+input[input.length - 1] + 1);

answered Jul 01 '19 at 05:25

Jonas Wilms

132,000
20
149
151

perfect and simple.+1 – Alive to die - Anant Jul 01 '19 at 05:28
"0.09" => "0.010" not sure it's what OP wants. – Kaiido Jul 01 '19 at 05:40
Close, but no cigar. As Kaiido notes, it increases the notation size. – matt Jul 01 '19 at 06:47

Syed mohamed aladeen · Accepted Answer · 2019-07-01T06:26:08.363

0

I tried your code, it is working fine to add I used parseFloat , so I guess may be you are missing it as you haven't added that part of code.

MODIFIED:

I have modified the snippet as it didn't support some of the numbers. now it will give your desired output..

function floatNum(floatNumber){
  
  let position = floatNumber.indexOf(".");
  if(position == -1){
    return +floatNumber+1;
  } else {
    let len = floatNumber.length;
    let a = "0".repeat(len-2)+'1';
    let dec = len-position-1;
    let add = [a.slice(0, position), ".", a.slice(position)].join('');
    return (parseFloat(floatNumber) + parseFloat(add)).toFixed(dec);
  }
}
console.log(floatNum('0.01'))
console.log(floatNum('10.12'))
console.log(floatNum('1'))
console.log(floatNum('123'))

edited Jul 01 '19 at 06:26

answered Jul 01 '19 at 05:04

Syed mohamed aladeen

6,507
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Yes can you run my snippet, it gives the output as `10.23` – Syed mohamed aladeen Jul 01 '19 at 05:12
1

Agreed. I didn't saw this answer before posting mine, but yours is definitely more correct than the highest voted one. I would just add a safe-guard against integers input which will break your logic (e.g `floatNum("123")` => `"123.100"`) and against less than 2 length inputs (e.g floatNum("1") => RangeError). – Kaiido Jul 01 '19 at 06:19
@Kaiido Thanks for the explanation, I'm trying to fix those – Syed mohamed aladeen Jul 01 '19 at 06:26
1

@Kaiido fixed the changes – Syed mohamed aladeen Jul 01 '19 at 06:29
1

Good enough for me ;-) (but since these were edge cases, I guess your prior example inputs where actually better for the current question) – Kaiido Jul 01 '19 at 06:33
1

Perfect! This is exactly the input > output i need. Thanks a heap Dood. – matt Jul 01 '19 at 06:50

How to increment a float by lowest zero

2 Answers2