How to add validation for positive floating point number with 3 digits before decimal?

Question

I have seen many links for floating point number validation but none of them for precision.

I want the field to display error if the input is 1234.31 or . but not for 123.5555555 or .3433 or.9022. I need the rules to be specified to get 0 to 3 digit before decimal. I tried

/^[^+-][0-9]{0,3}[.]?[0-9]{0,2}/

But it didn't work.

Amit Joki · Accepted Answer · 2014-04-03T06:10:59.053

2

Use this regex:

/^\d{0,3}\.\d+/

But if you want to use your regex, modify it like this:

/^[^+-][0-9]{0,3}[.]?[0-9]+/

Your original regex didn't work because you were making it to match only up to 2 decimal places. + in regex means 1 or many.

edited Apr 03 '14 at 06:10

answered Apr 03 '14 at 06:00

Amit Joki

58,320
7
77
95

Thanks, but how to restrict if the input is just 256.? – Abel Apr 03 '14 at 06:11
are you coming to say `256.`? – Amit Joki Apr 03 '14 at 06:12
Use my regex for that. That will do – Amit Joki Apr 03 '14 at 06:13
Yes, use my regex for that. My regex will make sure that numbers before `.` are 0 to 3 digits and it has a `.` and followed by some digits. – Amit Joki Apr 03 '14 at 06:15
No Joki, its not working. its through error when I tried 256. – Abel Apr 03 '14 at 06:16
array('weight','match', 'pattern'=>'/^\d{0,3}\.\d+/','message'=>'Add 0 to 3 digits before decimal'), – Abel Apr 03 '14 at 06:17
so is `256.` valid or not? – Amit Joki Apr 03 '14 at 06:18
decimal should have atleast some characters after `.` – Amit Joki Apr 03 '14 at 06:19
Thanks jogi, is that possible to make it accept numbers without decimal as well.256 – Abel Apr 03 '14 at 06:26
Use this regex: `/^\d{0,3}\.?\d*/` – Amit Joki Apr 03 '14 at 06:27
Thanks again Joki, last concern, I don't want it to accept plain "."? – Abel Apr 03 '14 at 06:32
@Abel, my name is Amit. Also it won't accept a plain `.` – Amit Joki Apr 03 '14 at 06:33
Sorry Amit, I just used it as it is in the profile name. – Abel Apr 03 '14 at 06:41
Now I just add one more rule and its fine now. array('height,weight','numerical', 'integerOnly'=>false), – Abel Apr 03 '14 at 06:41

Class · Answer 2 · 2014-04-03T06:39:33.453

0

You pretty much had it

/^([0-9]{0,3})?\.[0-9]+|[0-9]+$/

and use something like

if(!preg_match("^([0-9]{0,3})?\.[0-9]+|[0-9]+$/", $float)){}

edited Apr 03 '14 at 06:39

answered Apr 03 '14 at 06:08

Class

3,149
3
22
31

Thanks, my concern is not much about the digits after decimal. Is that possible to make it accept digits without decimals as well, but not accepting a plain "." – Abel Apr 03 '14 at 06:35
@Abel Try my regex out and see for yourself but use a `!` 'not'. Or use this [test](https://www.debuggex.com/r/8dERfrSGUczd1ZBW) here by changing the `result` item. – Class Apr 03 '14 at 06:38

How to add validation for positive floating point number with 3 digits before decimal?

2 Answers2