Data validity and syntax

I tried to follow the specifications of the following link:

https://en.wikipedia.org/wiki/Permanent_account_number 

Test if this function is right for you. 

let
checkPAN=(PAN as text) as logical =>
let
charsPAN=Text.ToList(PAN),
fourthChars=Text.ToList("ABCEFGHLJPT"),
len=Text.Length(PAN)=10,
upper=Text.Upper(PAN)=PAN,
btwAAAZZZ="AAA"<=Text.Start(PAN,3) and Text.Start(PAN,3)<="ZZZ",
fourthChar=List.Contains(fourthChars,charsPAN{3}),
fifthChar="A" < charsPAN{4} and charsPAN{4} <"Z",
digitsPAN="0000"<Text.Range(PAN,5,4) and Text.Range(PAN,5,4)<"9999",
lastCharPAN="A" < charsPAN{9} and charsPAN{9} <"Z"
in len and upper and btwAAAZZZ and fourthChar and digitsPAN and lastCharPAN
in checkPAN

Hi Anonymous ,

You could refer to the following DAX:

Column =
VAR a =
    LEFT ( 'Table'[Column1], 5 )
VAR b1 =
    MID ( 'Table'[Column1], 1, 1 )
VAR b2 =
    MID ( 'Table'[Column1], 2, 1 )
VAR b3 =
    MID ( 'Table'[Column1], 3, 1 )
VAR b4 =
    MID ( 'Table'[Column1], 4, 1 )
VAR b5 =
    MID ( 'Table'[Column1], 5, 1 )
VAR b =
    ISERROR ( VALUE ( b1 ) ) && ISERROR ( VALUE ( b2 ) )
        && ISERROR ( VALUE ( b3 ) )
        && ISERROR ( VALUE ( b4 ) )
        && ISERROR ( VALUE ( b5 ) )
VAR c =
    NOT ( ISERROR ( VALUE ( MID ( 'Table'[Column1], 6, 4 ) ) ) )
VAR d =
    EXACT ( UPPER ( RIGHT ( 'Table'[Column1], 1 ) ), RIGHT ( 'Table'[Column1], 1 ) )
VAR e =
    ISERROR ( VALUE ( RIGHT ( 'Table'[Column1], 1 ) ) )
VAR f =
    CALCULATE (
        COUNTA ( 'Table'[Column1] ),
        ALLEXCEPT ( 'Table', 'Table'[Column1] )
    ) = 1
VAR g = b4 IN { "P", "C", "H", "F", "A", "T", "B", "L", "J", "G" }
RETURN
    IF (
        EXACT ( UPPER ( a ), a ) && ISTEXT ( a )
            && b
            && c
            && d
            && e
            && f
            && g,
        1,
        0
    )