Honestly, I thought it would be easy to find a regex that would match something like:
1,234.56 OR 1234.56 OR 123,456.789029329 or even 223.233434332 etc.
But it wasn’t. I found some but they didn’t quite work or
Anywhere here is the regex I crafted and settled on:
**^(\d  )?(\d  ,\d{3})\.?\d$** 
It isn’t perfect, but it is as close as I could manage. Here are some matches:
 1322.23
 1,322.23
 1,322
 1132
Here are some numbers that fail to match
 1,32
 1,32,2
 1320.223,232
So, in general this works great but it is possible to get by the regex somewhat because I just am not strong enough with regex’s at the moment to fix it:
Here is an example:
 1,2345,232
Notice there are four numbers between the first and the second commas. My rule insists there has to be at least 3 numbers but doesn’t insist on a comma before the next number. The reason for this is the fact that I don’t want commas to be required before the decimal point. My initial effort which insisted on three numbers after the first comma and a second comma before the next three numbers etc required that any number in the thousands or higher had to have a comma if I wanted to use a decimal point. That wasn’t acceptable so the current regex is my best compromise.
If you can offer one better let me know in the comments.
Comments
AdamNation
Try this:
^0(\.0)?$^(?0?\.0[19]\d)$^(?19(
.\d)?)$
It doesn’t allow trailing zeros (“012”) (“0.000x” is allowed). Negative zero is not allowed. A number is valid if it ends with a period, as in “12.”
Bill
Sorry that doesn’t work.
I just tested it and with the number
1,234.232.232 it fails in two ways:
first, it selects 234.232.232 so it drops off the 1, and it allows multiple decimal points.
AdamNation
The following is untested, but I think it may be on the right track, unless I’m breaking the regex engine somehow…
Basically, it first tries to match “0”. If it can’t, it tries to match 1 < x < 1. If it still fails, it tries to match ddddd.ddddd with optional commas. No leading 0’s are allowed.
The only problem I see is that 0.0000 is currently allowed, but I think that could be resolved.
0

?0?.\d+

?[19]
(
(\d{0,2},(\d{3},)\d{3}) 
(\d)
)
(.\d*)?
$