I am trying to write a regular expression which has to adhere the following rules:
Y120.001/100.232k
↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑
| | | | | | | | This k may be any letter, is not required
| | | | | | | Another number if there was a dot
| | | | | | A dot, not required
| | | | | A number with at least one digit, not required if a letter follows
| | | | Always a slash
| | | If there's a dot, digits can follow
| | A dot, not required
| A number, at least one digit
Always Y
These strings should work:
These should not work:
This is my early attempt, but it does not work in PHP:
/^\$*(\d)*(.*(\d))\/*(.*(\d))*.$
try this:
/Y\d+\.?\d*\/\d+\.?\d*\w?/
In javascript
re=/^Y\d+(\.\d+)?\/([a-z]$|\d+(\.\d+)?[a-z]?$)/
"Y120.001/1k Y1/h Y2039/100 Y29/47.0".split(" ").map(function(s) { return re.test(s) })
> [true, true, true, true]
"x203/493s Y/39x Y83839 Y78/29".split(" ").map(function(s) { return re.test(s) })
> [false, false, false, true]
This does accept Y78/29 as the trailing letter is optional.
^Y\d+\.?\d*/((\d+\.?\d*)[a-zA-Z]?|(\d+\.?\d*)?[a-zA-Z])$
You can check the explanation of the regex from here.
After several iterations to correct for commented shortcomings:
/^Y\d+(?:\.\d+)?\/(?:(?:\d+(?:\.\d+)?)[A-Za-z]?|[A-Za-z])$/
Old Answer:
Here is a fully specific version that works well.
/^Y\d+(?:\.\d+)?\/(\d+(?:\.\d+)?)?[A-Za-z]?$/
Edited for a follow-up test in jsfiddle
If I understand the nuances of your specification
\bY\d+(?:\.\d*)?/(?:[A-Za-z]|(?:\d+(?:\.\d+)?[A-Za-z]?))\b
I understand your specification to include that if the first dot is present, the following number(s) is/are optional; but if the 2nd dot is present, there must be at least one following number. Others seem to have interpreted that part of your requirements differently.
this pattern should work Y[\d.]+\/[\d.]*[a-z]? Demo
What about the following one?
var r = /^Y\d+(\.\d+)?\/(\d+(\.\d+)?|(\d+(\.\d+)?)?[A-Za-z])$/;
console.log(true === r.test('Y120.001/1k')); // true
console.log(true === r.test('Y1/h')); // true
console.log(true === r.test('Y2039/100')); // true
console.log(true === r.test('Y29/47.0')); // true
console.log(false === r.test('x203/493s')); // true
console.log(false === r.test('Y/39x')); // true
console.log(false === r.test('Y83839')); // true