Regular expression to test and limit number of characters

[Sharkie]

I need a regular expression to evaluate a text input field. The
validation rules are:

1) only A-Z and 0-9 chars allowed,
2) only one alpha char allowed (at any position) - rest are digits,
3) total length must be between 9 and 12 chars,

a valid example would be "123A456789 "

I can enforce the first two rules by using this:

/^\d*[A-Z]\d*$/

but not limit chars between 9 and 12. The following doesn't work:

/^(\d*[A-Z]\d*){9,12}$/

because of the asterisk which can be any numbers of chars. Since I
don't know where the alpha character
will be I'm having hard time limiting number of digits either before
or after it.

What's a good way to enforce above rules. This should ideally be one
reg exp.

[Bart Van der Donck]

Sharkie wrote:

I need a regular expression to evaluate a text input field. The
validation rules are:

1) only A-Z and 0-9 chars allowed,
2) only one alpha char allowed (at any position) - rest are digits,
3) total length must be between 9 and 12 chars,

a valid example would be "123A456789 "

/^\d{8,11}$/.test(str.repla ce(/[A-Z]/,''))&&/[A-Z]/.test(str)

--
Bart

[Evertjan.]

Bart Van der Donck wrote on 28 feb 2008 in comp.lang.javas cript:

Sharkie wrote:

>I need a regular expression to evaluate a text input field. The
validation rules are:

1) only A-Z and 0-9 chars allowed,
2) only one alpha char allowed (at any position) - rest are digits,
3) total length must be between 9 and 12 chars,

a valid example would be "123A456789 "

/^\d{8,11}$/.test(str.repla ce(/[A-Z]/,'')) && /[A-Z]/.test(str)

"only one alpha char allowed" != "must have one and only one alpha char"

/^[\dA-Z]{9,12}$/.test(str) && str.replace(/\d/g,'').length<2

--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Bart Van der Donck]

Evertjan. wrote:

Bart Van der Donck wrote on 28 feb 2008 in comp.lang.javas cript:

>/^\d{8,11}$/.test(str.repla ce(/[A-Z]/,'')) && /[A-Z]/.test(str)

"only one alpha char allowed" != "must have one and only one alpha char"

/^[\dA-Z]{9,12}$/.test(str) && str.replace(/\d/g,'').length<2

Looking at his regex attempts, I think the original poster meant "must
have one and only one alpha char".

--
Bart

[Bart Van der Donck]

Evertjan. wrote:

/^[\dA-Z]{9,12}$/.test(str) && str.replace(/\d/g,'').length<2

Identical, but more terse:

/^\d{9,12}$/.test(str.repla ce(/[A-Z]/,1))

--
Bart

[RobG]

Bart Van der Donck wrote:

Evertjan. wrote:

>/^[\dA-Z]{9,12}$/.test(str) && str.replace(/\d/g,'').length<2

Identical, but more terse:

/^\d{9,12}$/.test(str.repla ce(/[A-Z]/,1))

Where does the (optional or mandatory) letter fit in the first RegExpr?
--
Rob

[RobG]

RobG wrote:

Bart Van der Donck wrote:

>Evertjan. wrote:

>>/^[\dA-Z]{9,12}$/.test(str) && str.replace(/\d/g,'').length<2

Identical, but more terse:

/^\d{9,12}$/.test(str.repla ce(/[A-Z]/,1))

Where does the (optional or mandatory) letter fit in the first RegExpr?

Ah, OK, I got it - the replace takes care of it first. I'm a bit slower
than usual tonight.

--
Rob

[pr]

Sharkie wrote:

I need a regular expression to evaluate a text input field. The
validation rules are:

1) only A-Z and 0-9 chars allowed,
2) only one alpha char allowed (at any position) - rest are digits,
3) total length must be between 9 and 12 chars,

a valid example would be "123A456789 "

[...]

What's a good way to enforce above rules. This should ideally be one
reg exp.

For fun only, here's a version that uses a single expression:

/^(\d(?=\d*[A-Z])|[A-Z](?!.*[A-Z])|\d(?=\d*$)){9 ,12}$/

or if the single alpha character is optional:

/^(\d|[A-Z](?!.*[A-Z])){9,12}$/

Not something you would want to use in public.

[Evertjan.]

RobG wrote on 28 feb 2008 in comp.lang.javas cript:

RobG wrote:

>Bart Van der Donck wrote:

>>Evertjan. wrote:

/^[\dA-Z]{9,12}$/.test(str) && str.replace(/\d/g,'').length<2

Identical, but more terse:

/^\d{9,12}$/.test(str.repla ce(/[A-Z]/,1))

Where does the (optional or mandatory) letter fit in the first RegExpr?

Ah, OK, I got it - the replace takes care of it first. I'm a bit slower
than usual tonight.

I like Bart's solution.
That's what the joy of programming is about.

[But it does not cover the mandatoriness of an upperalpha! ;-) ]

An alternative not using test():

!str.replace(/[A-Z]/,1).replace(/\d{9,12}/,'')

--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)