Validate International Securities Identification Number
You are encouraged to solve this task according to the task description, using any language you may know.
An International Securities Identification Number (ISIN) is a unique international identifier for a financial security such as a stock or bond.
Write a function or program that takes a string as input, and checks whether it is a valid ISIN.
It is only valid if it has the correct format, and the embedded checksum is correct.
Demonstrate that your code passes the test-cases listed below.
The format of an ISIN is as follows:
For this task, you may assume that any 2-character alphabetic sequence is a valid country code.
The checksum can be validated as follows:
- Replace letters with digits, by converting each character from base 36 to base 10, e.g.
AU0000XVGZA3→1030000033311635103. - Perform the Luhn test on this base-10 number.
There is a separate task for this test: Luhn test of credit card numbers.
You don't have to replicate the implementation of this test here – you can just call the existing function from that task. (Add a comment stating if you did this.)
| ISIN | Validity | Comment |
|---|---|---|
| US0378331005 | valid | |
| US0373831005 | not valid | The transposition typo is caught by the checksum constraint. |
| U50378331005 | not valid | The substitution typo is caught by the format constraint. |
| US03378331005 | not valid | The duplication typo is caught by the format constraint. |
| AU0000XVGZA3 | valid | |
| AU0000VXGZA3 | valid | Unfortunately, not all transposition typos are caught by the checksum constraint. |
| FR0000988040 | valid |
(The comments are just informational. Your function should simply return a Boolean result. See #Perl_6 for a reference solution.)
Useful resources:
- Interactive online ISIN validator
- Wikipedia article: International Securities Identification Number
Related tasks:
Ada
Calling the existing Luhn algorithm implementation from the Luhn test of credit card numbers task.
<lang Ada>procedure ISIN is
-- Luhn_Test copied from other Task
function Luhn_Test (Number: String) return Boolean is
Sum : Natural := 0;
Odd : Boolean := True;
Digit: Natural range 0 .. 9;
begin
for p in reverse Number'Range loop
Digit := Integer'Value (Number (p..p));
if Odd then
Sum := Sum + Digit;
else
Sum := Sum + (Digit*2 mod 10) + (Digit / 5);
end if;
Odd := not Odd;
end loop;
return (Sum mod 10) = 0;
end Luhn_Test;
subtype Decimal is Character range '0' .. '9';
subtype Letter is Character range 'A' .. 'Z';
subtype ISIN_Type is String(1..12);
-- converts a string of decimals and letters into a string of decimals
function To_Digits(S: String) return String is
-- Character'Pos('A')-Offset=10, Character'Pos('B')-Offset=11, ...
Offset: constant Integer := Character'Pos('A')-10;
Invalid_Character: exception;
begin
if S = "" then
return "";
elsif S(S'First) = ' ' then -- skip blanks
return To_Digits(S(S'First+1 .. S'Last));
elsif S(S'First) in Decimal then
return S(S'First) & To_Digits(S(S'First+1 .. S'Last));
elsif S(S'First) in Letter then
return To_Digits(Integer'Image(Character'Pos(S(S'First))-Offset))
& To_Digits(S(S'First+1 .. S'Last));
else
raise Invalid_Character;
end if;
end To_Digits;
function Is_Valid_ISIN(S: ISIN_Type) return Boolean is
Number : String := To_Digits(S);
begin
return S(S'First) in Letter and
S(S'First+1) in Letter and
S(S'Last) in Decimal and
Luhn_Test(Number);
end Is_Valid_ISIN;
Test_Cases : constant Array(1..6) of ISIN_Type :=
("US0378331005",
"US0373831005",
"U50378331005",
-- excluded by type with fixed length
-- "US03378331005",
"AU0000XVGZA3",
"AU0000VXGZA3",
"FR0000988040");
begin
for I in Test_Cases'Range loop
Ada.Text_IO.Put_Line(Test_Cases(I) & ":" &
Boolean'Image(Is_Valid_ISIN(Test_Cases(I))));
end loop;
-- using wrong length will result in an exception:
Ada.Text_IO.Put("US03378331005:");
Ada.Text_IO.Put_Line(Boolean'Image(Is_Valid_Isin("US03378331005")));
exception
when others =>
Ada.Text_IO.Put_Line("Exception occured");
end ISIN;</lang>
Output:
US0378331005:TRUE US0373831005:FALSE U50378331005:FALSE AU0000XVGZA3:TRUE AU0000VXGZA3:TRUE FR0000988040:TRUE US03378331005:Exception occured
ALGOL W
Uses the LuhnTest procedure from the Luhn test of credit card numbers task. <lang algolw>begin
% external procedure that returns true if ccNumber passes the Luhn test, false otherwise %
logical procedure LuhnTest ( string(32) value ccNumber
; integer value ccLength
) ; algol "LUHN" ;
% returns true if isin is a valid ISIN, false otherwise %
logical procedure isIsin ( string(32) value isin ) ;
if isin( 12 // 20 ) not = "" then false % code is too long %
else begin
% the first two characters must be upper-case letters %
% returns the digit corresponding to a character of an ISIN %
integer procedure isinDigit ( string(1) value iChar ) ;
if iChar >= "0" and iChar <= "9" then ( decode( iChar ) - decode( "0" ) )
else if iChar >= "A" and iChar <= "Z" then ( decode( iChar ) - decode( "A" ) ) + 10
else begin % invalid digit %
isValid := false;
-1
end isinDigit ;
integer d1, d2;
logical isValid;
isValid := true;
d1 := isinDigit( isin( 0 // 1 ) );
d2 := isinDigit( isin( 1 // 1 ) );
if d1 < 10 or d1 > 35 or d2 < 10 or d2 > 35 then false % invalid first two characters %
else begin
% ok so far - conveet from base 36 to base 10 %
string(24) base10Isin;
integer b10Pos;
base10Isin := "";
b10Pos := 0;
for cPos := 0 until 10 do begin
integer digit;
digit := isinDigit( isin( cPos // 1 ) );
if isValid then begin
% valid digit %
if digit > 9 then begin
base10Isin( b10Pos // 1 ) := code( ( digit div 10 ) + decode( "0" ) );
b10Pos := b10Pos + 1;
end if_digit_gt_9 ;
base10Isin( b10Pos // 1 ) := code( ( digit rem 10 ) + decode( "0" ) );
b10Pos := b10Pos + 1
end if_isValid
end for_cPos ;
% add the check digit as is %
base10Isin( b10Pos // 1 ) := isin( 11 // 1 );
isValid and LuhnTest( base10Isin, b10Pos + 1 )
end
end isIsin ;
% task test cases %
procedure testIsIsin ( string(32) value isin
; logical value expected
) ;
begin
logical isValid;
isValid := isIsin( isin );
write( s_w := 0
, isin
, if isValid then " is valid" else " is invalid"
, if isValid = expected then "" else " NOT as expected ??"
)
end testIsin ;
testIsIsin( "US0378331005", true ); testIsIsin( "US0373831005", false ); testIsIsin( "U50378331005", false ); testIsIsin( "US03378331005", false ); testIsIsin( "AU0000XVGZA3", true ); testIsIsin( "AU0000VXGZA3", true ); testIsIsin( "FR0000988040", true );
end.</lang>
- Output:
US0378331005 is valid US0373831005 is invalid U50378331005 is invalid US03378331005 is invalid AU0000XVGZA3 is valid AU0000VXGZA3 is valid FR0000988040 is valid
C
<lang c>#include <stdio.h>
int check_isin(char *a) {
int i, j, k, v, s[24];
j = 0;
for(i = 0; i < 12; i++) {
k = a[i];
if(k >= '0' && k <= '9') {
if(i < 2) return 0;
s[j++] = k - '0';
} else if(k >= 'A' && k <= 'Z') {
if(i == 11) return 0;
k -= 'A' - 10;
s[j++] = k / 10;
s[j++] = k % 10;
} else {
return 0;
}
}
if(a[i]) return 0;
v = 0;
for(i = j - 2; i >= 0; i -= 2) {
k = 2 * s[i];
v += k > 9 ? k - 9 : k;
}
for(i = j - 1; i >= 0; i -= 2) {
v += s[i];
}
return v % 10 == 0;
}
int main() {
char *test[7] = {"US0378331005", "US0373831005", "U50378331005",
"US03378331005", "AU0000XVGZA3", "AU0000VXGZA3",
"FR0000988040"};
int i;
for(i = 0; i < 7; i++) printf("%c%c", check_isin(test[i]) ? 'T' : 'F', i == 6 ? '\n' : ' ');
return 0;
}
/* will print: T F F F T T T */</lang>
Caché ObjectScript
<lang cos>Class Utils.Check [ Abstract ] {
ClassMethod ISIN(x As %String) As %Boolean { // https://en.wikipedia.org/wiki/International_Securities_Identification_Number IF x'?2U9UN1N QUIT 0 SET cd=$EXTRACT(x,*), x=$EXTRACT(x,1,*-1) FOR i=1:1 { SET n=$EXTRACT(x,i) IF n="" QUIT IF n'=+n SET $EXTRACT(x,i)=$CASE(n,"*":36,"@":37,"#":38,:$ASCII(n)-55) } // call into luhn check, appending check digit QUIT ..Luhn(x_cd) }
ClassMethod Luhn(x As %String) As %Boolean { // https://www.simple-talk.com/sql/t-sql-programming/calculating-and-verifying-check-digits-in-t-sql/ SET x=$TRANSLATE(x," "), cd=$EXTRACT(x,*) SET x=$REVERSE($EXTRACT(x,1,*-1)), t=0 FOR i=1:1:$LENGTH(x) { SET n=$EXTRACT(x,i) IF i#2 SET n=n*2 IF $LENGTH(n)>1 SET n=$EXTRACT(n,1)+$EXTRACT(n,2) SET t=t+n } QUIT cd=((t*9)#10) }
}</lang>
- Examples:
USER>For { Read isin Quit:isin="" Write ": "_##class(Utils.Check).ISIN(isin), ! }
US0378331005: 1
US0373831005: 0
U50378331005: 0
US03378331005: 0
AU0000XVGZA3: 1
AU0000VXGZA3: 1
FR0000988040: 1
USER>
COBOL
By Steve Williams
<lang cobol> >>SOURCE FORMAT FREE
- > this is gnucobol 2.0
identification division. program-id. callISINtest. data division. working-storage section. 01 ISINtest-result binary-int. procedure division. start-callISINtest.
display 'should be valid ' with no advancing call 'ISINtest' using 'US0378331005' ISINtest-result perform display-ISINtest-result display 'should not be valid ' with no advancing call 'ISINtest' using 'US0373831005' ISINtest-result perform display-ISINtest-result display 'should not be valid ' with no advancing call 'ISINtest' using 'U50378331005' ISINtest-result perform display-ISINtest-result display 'should not be valid ' with no advancing call 'ISINtest' using 'US03378331005' ISINtest-result perform display-ISINtest-result display 'should be valid ' with no advancing call 'ISINtest' using 'AU0000XVGZA3' ISINtest-result perform display-ISINtest-result display 'should be valid ' with no advancing call 'ISINtest' using 'AU0000VXGZA3' ISINtest-result perform display-ISINtest-result display 'should be valid ' with no advancing call 'ISINtest' using 'FR0000988040' ISINtest-result perform display-ISINtest-result stop run .
display-ISINtest-result.
evaluate ISINtest-result
when 0
display ' is valid'
when -1
display ' invalid length '
when -2
display ' invalid countrycode '
when -3
display ' invalid base36 digit '
when -4
display ' luhn test failed'
when other
display ' invalid return code ' ISINtest-result
end-evaluate
.
end program callISINtest.
identification division. program-id. ISINtest. data division. working-storage section. 01 country-code-values value
'ADAEAFAGAIALAMAOAQARASATAUAWAXAZBABBBDBEBFBGBHBIBJBLBMBNBOBQBRBS'
& 'BTBVBWBYBZCACCCDCFCGCHCICKCLCMCNCOCRCUCVCWCXCYCZDEDJDKDMDODZECEE' & 'EGEHERESETFIFJFKFMFOFRGAGBGDGEGFGGGHGIGLGMGNGPGQGRGSGTGUGWGYHKHM' & 'HNHRHTHUIDIEILIMINIOIQIRISITJEJMJOJPKEKGKHKIKMKNKPKRKWKYKZLALBLC' & 'LILKLRLSLTLULVLYMAMCMDMEMFMGMHMKMLMMMNMOMPMQMRMSMTMUMVMWMXMYMZNA' & 'NCNENFNGNINLNONPNRNUNZOMPAPEPFPGPHPKPLPMPNPRPSPTPWPYQARERORSRURW' & 'SASBSCSDSESGSHSISJSKSLSMSNSOSRSSSTSVSXSYSZTCTDTFTGTHTJTKTLTMTNTO' & 'TRTTTVTWTZUAUGUMUSUYUZVAVCVEVGVIVNVUWFWSYEYTZAZMZW'.
03 country-codes occurs 249
ascending key country-code
indexed by cc-idx.
05 country-code pic xx.
01 b pic 99. 01 base36-digits pic x(36) value
'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'.
01 i pic 99. 01 p pic 99. 01 luhn-number pic x(20). 01 luhntest-result binary-int.
linkage section. 01 test-number any length. 01 ISINtest-result binary-int.
procedure division using test-number ISINtest-result. start-ISINtest.
display space test-number with no advancing
*> format test
if function length(test-number) <> 12
move -1 to ISINtest-result
goback
end-if
*> countrycode test
search all country-codes
at end
move -2 to ISINtest-result
goback
when test-number(1:2) = country-code(cc-idx)
continue
end-search
*> convert each character from base 36 to base 10
*> and add to the luhn-number
move 0 to p
perform varying i from 1 by 1 until i > 12
if test-number(i:1) >= '0' and <= '9'
move test-number(i:1) to luhn-number(p + 1:1)
add 1 to p
else
perform varying b from 9 by 1 until b > 35
or base36-digits(b + 1:1) = test-number(i:1)
continue
end-perform
if b > 35
move -3 to ISINtest-result
goback
end-if
move b to luhn-number(p + 1:2)
add 2 to p
end-if
end-perform
call 'luhntest' using luhn-number(1:p) luhntest-result
if luhntest-result <> 0
move -4 to ISINtest-result
goback
end-if
move 0 to ISINtest-result goback .
end program ISINtest.
identification division. program-id. luhntest. data division. working-storage section. 01 i pic S99. 01 check-sum pic 999. linkage section. 01 test-number any length. 01 luhntest-result binary-int. procedure division using test-number luhntest-result. start-luhntest.
display space test-number with no advancing move 0 to check-sum
*> right to left sum the odd numbered digits
compute i = function length(test-number)
perform varying i from i by -2 until i < 1
add function numval(test-number(i:1)) to check-sum
end-perform
display space check-sum with no advancing
*> right to left double sum the even numbered digits
compute i = function length(test-number) - 1
perform varying i from i by -2 until i < 1
add function numval(test-number(i:1)) to check-sum
add function numval(test-number(i:1)) to check-sum
*> convert a two-digit double sum number to a single digit
if test-number(i:1) >= '5'
subtract 9 from check-sum
end-if
end-perform
display space check-sum with no advancing
if function mod(check-sum,10) = 0
move 0 to luhntest-result *> success
else
move -1 to luhntest-result *> failure
end-if
goback
.
end program luhntest.</lang>
- Output:
prompt$ cobc -xj ISINTest.cbl should be valid US0378331005 30280378331005 027 050 is valid should not be valid US0373831005 30280373831005 022 046 luhn test failed should not be valid U50378331005 invalid countrycode should not be valid US03378331005 invalid length should be valid AU0000XVGZA3 1030000033311635103 018 030 is valid should be valid AU0000VXGZA3 1030000031331635103 018 030 is valid should be valid FR0000988040 15270000988040 020 050 is valid
Common Lisp
<lang lisp>(defun alphap (char)
(char<= #\A char #\Z))
(defun alpha-digit-char-p (char)
(or (alphap char) (digit-char-p char)))
(defun valid-isin-format-p (isin)
(and (= (length isin) 12)
(alphap (char isin 0))
(alphap (char isin 1))
(loop for i from 2 to 10
always (alpha-digit-char-p (char isin i)))
(digit-char-p (char isin 11))))
(defun isin->digits (isin)
(apply #'concatenate 'string
(loop for c across isin
collect (princ-to-string (digit-char-p c 36)))))
(defun luhn-test (string)
(loop for c across (reverse string)
for oddp = t then (not oddp)
if oddp
sum (digit-char-p c) into result
else
sum (let ((n (* 2 (digit-char-p c))))
(if (> n 9) (- n 9) n))
into result
finally (return (zerop (mod result 10)))))
(defun valid-isin-p (isin)
(and (valid-isin-format-p isin)
(luhn-test (isin->digits isin))))
(defun test ()
(dolist (isin '("US0378331005" "US0373831005" "U50378331005" "US03378331005"
"AU0000XVGZA3" "AU0000VXGZA3" "FR0000988040"))
(format t "~A: ~:[invalid~;valid~]~%" isin (valid-isin-p isin))))</lang>
- Output:
US0378331005: valid US0373831005: invalid U50378331005: invalid US03378331005: invalid AU0000XVGZA3: valid AU0000VXGZA3: valid FR0000988040: valid
Elixir
used Luhn module from here <lang elixir>isin? = fn str ->
if str =~ ~r/\A[A-Z]{2}[A-Z0-9]{9}\d\z/ do
String.codepoints(str)
|> Enum.map_join(&String.to_integer(&1, 36))
|> Luhn.valid?
else
false
end
end
IO.puts " ISIN Valid?" ~w(US0378331005
US0373831005 U50378331005 US03378331005 AU0000XVGZA3 AU0000VXGZA3 FR0000988040)
|> Enum.each(&IO.puts "#{&1}\t#{isin?.(&1)}")</lang>
- Output:
ISIN Valid? US0378331005 true US0373831005 false U50378331005 false US03378331005 false AU0000XVGZA3 true AU0000VXGZA3 true FR0000988040 true
Fortran
<lang fortran>program isin
use ctype
implicit none
character(20) :: test(7) = ["US0378331005 ", &
"US0373831005 ", &
"U50378331005 ", &
"US03378331005 ", &
"AU0000XVGZA3 ", &
"AU0000VXGZA3 ", &
"FR0000988040 "]
print *, check_isin(test)
contains
elemental logical function check_isin(a)
character(*), intent(in) :: a
integer :: s(24)
integer :: i, j, k, n, v
check_isin = .false.
n = len_trim(a)
if (n /= 12) return
! Convert to an array of digits
j = 0
do i = 1, n
k = iachar(a(i:i))
if (k >= 48 .and. k <= 57) then
if (i < 3) return
k = k - 48
j = j + 1
s(j) = k
else if (k >= 65 .and. k <= 90) then
if (i == 12) return
k = k - 65 + 10
j = j + 1
s(j) = k / 10
j = j + 1
s(j) = mod(k, 10)
else
return
end if
end do
! Compute checksum
v = 0
do i = j - 1, 1, -2
k = 2 * s(i)
if (k > 9) k = k - 9
v = v + k
end do
do i = j, 1, -2
v = v + s(i)
end do
check_isin = 0 == mod(v, 10)
end function
end program</lang>
FreeBASIC
<lang freebasic>' version 27-10-2016 ' compile with: fbc -s console
- Ifndef TRUE ' define true and false for older freebasic versions
#Define FALSE 0 #Define TRUE Not FALSE
- EndIf
Function luhntest(cardnr As String) As Long
cardnr = Trim(cardnr) ' remove spaces
Dim As String reverse_nr = cardnr Dim As Long i, j, s1, s2, l = Len(cardnr) -1
' reverse string
For i = 0 To l
reverse_nr[i] = cardnr[l - i]
Next
' sum odd numbers
For i = 0 To l Step 2
s1 = s1 + (reverse_nr[i] - Asc("0"))
Next
' sum even numbers
For i = 1 To l Step 2
j = reverse_nr[i] - Asc("0")
j = j * 2
If j > 9 Then j = j Mod 10 +1
s2 = s2 + j
Next
If (s1 + s2) Mod 10 = 0 Then
Return TRUE
Else
Return FALSE
End If
End Function
' ------=< MAIN >=-----
Dim As String test_str Dim As String test_set(1 To ...) = { "US0378331005", "US0373831005", _
"U50378331005", "US03378331005", "AU0000XVGZA3", _
"AU0000VXGZA3", "FR0000988040" }
Dim As Long i, l, n, x
For i = 1 To UBound(test_set)
test_str = ""
l = Len(test_set(i))
If l <> 12 Then
Print test_set(i), "Invalid, length <> 12 char."
Continue For
End If
If test_set(i)[0] < Asc("A") Or test_set(i)[1] < Asc("A") Then
Print test_set(i), "Invalid, number needs to start with 2 characters"
Continue For
End If
For n = 0 To l -1
x = test_set(i)[n] - Asc("0")
' if test_set(i)[i] is a letter we to correct for that
If x > 9 Then x = x -7
If x < 10 Then
test_str = test_str + Str(x)
Else ' two digest number
test_str = test_str + Str(x \ 10) + Str(x Mod 10)
End If
Next
Print test_set(i), IIf(luhntest(test_str) = TRUE, "Valid","Invalid, checksum error")
Next
' empty keyboard buffer
While InKey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End</lang>
- Output:
US0378331005 Valid US0373831005 Invalid, checksum error U50378331005 Invalid, number needs to start with 2 characters US03378331005 Invalid, length <> 12 char. AU0000XVGZA3 Valid AU0000VXGZA3 Valid FR0000988040 Valid
Go
<lang go>package main
import "regexp"
var r = regexp.MustCompile(`^[A-Z]{2}[A-Z0-9]{9}\d$`)
var inc = [2][10]int{ {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, {0, 2, 4, 6, 8, 1, 3, 5, 7, 9}, }
func ValidISIN(n string) bool { if !r.MatchString(n) { return false } var sum, p int for i := 10; i >= 0; i-- { p = 1 - p if d := n[i]; d < 'A' { sum += inc[p][d-'0'] } else { d -= 'A' sum += inc[p][d%10] p = 1 - p sum += inc[p][d/10+1] } } sum += int(n[11] - '0') return sum%10 == 0 }</lang>
<lang go>package main
import "testing"
func TestValidISIN(t *testing.T) { testcases := []struct { isin string valid bool }{ {"US0378331005", true}, {"US0373831005", false}, {"U50378331005", false}, {"US03378331005", false}, {"AU0000XVGZA3", true}, {"AU0000VXGZA3", true}, {"FR0000988040", true}, }
for _, testcase := range testcases { actual := ValidISIN(testcase.isin) if actual != testcase.valid { t.Errorf("expected %v for %q, got %v", testcase.valid, testcase.isin, actual) } } }</lang>
Groovy
<lang groovy>CHARS = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
int checksum(String prefix) {
def digits = prefix.toUpperCase().collect { CHARS.indexOf(it).toString() }.sum()
def groups = digits.collect { CHARS.indexOf(it) }.inject([[], []]) { acc, i -> [acc[1], acc[0] + i] }
def ds = groups[1].collect { (2 * it).toString() }.sum().collect { CHARS.indexOf(it) } + groups[0]
(10 - ds.sum() % 10) % 10
}
assert checksum('AU0000VXGZA') == 3 assert checksum('GB000263494') == 6 assert checksum('US037833100') == 5 assert checksum('US037833107') == 0</lang>
Haskell
<lang Haskell>module ISINVerification2
where
import Data.Char ( isUpper , isDigit , digitToInt )
verifyISIN :: String -> Bool verifyISIN isin = correctFormat isin && mod (oddsum + multiplied_even_sum) 10 == 0
where
reverted = reverse $ convertToNumber isin
theOdds = fst $ collectOddandEven reverted
theEvens = snd $ collectOddandEven reverted
oddsum = sum $ map digitToInt theOdds
multiplied_even_sum = addUpDigits $ map ( (* 2 ) . digitToInt ) theEvens
capitalLetters :: [Char] capitalLetters = ['A' , 'B'..'Z']
numbers :: [Char] numbers = ['0' , '1' , '2', '3' , '4' , '5', '6' , '7' , '8' , '9' ]
correctFormat :: String -> Bool correctFormat isin = (length isin == 12 ) && ( all (\b -> elem b capitalLetters ) $ take 2 isin)
&& (all (\c -> elem c capitalLetters || elem c numbers) $ drop 2 $ take 11 isin)
&& (elem ( last isin ) numbers)
convertToNumber :: String -> String convertToNumber str = concat $ map convert str
where
convert :: Char -> String
convert c = if isDigit c then show $ digitToInt c else show ( fromEnum c - 55 )
collectOddandEven :: String -> (String , String ) collectOddandEven term
|odd $ length term = (concat [take 1 $ drop n term | n <- [0,2..length term - 1]] ,
concat [take 1 $ drop d term | d <- [1,3..length term - 2]] )
|otherwise = (concat [take 1 $ drop n term | n <- [0,2..length term -2]] ,
concat [take 1 $ drop d term | d <- [1,3..length term - 1]] )
addUpDigits :: [Int] -> Int
addUpDigits list = sum $ map (\d -> if d > 9 then sum $ map digitToInt $ show d else d ) list
printSolution :: String -> IO ( ) printSolution str = do
putStr $ str ++ " is" if verifyISIN str == True then putStrLn " valid" else putStrLn " not valid"
main :: IO ( ) main = do
let isinnumbers = ["US0378331005" , "US0373831005" , "US03378331005" , "AU0000XVGZA3" ,
"AU0000VXGZA3" , "FR0000988040"]
mapM_ printSolution isinnumbers</lang>
- Output:
US0378331005 is valid US0373831005 is not valid US03378331005 is not valid AU0000XVGZA3 is valid AU0000VXGZA3 is valid FR0000988040 is valid
J
<lang j>splt=: '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ' i. ' ' -.~ ": checksum=: 3 : '10| - +/ splt (* 2 1 $~ #) |. splt splt y'
assert 5 = checksum 'US037833100' assert 0 = checksum 'US037833107' assert 3 = checksum 'AU0000VXGZA' assert 6 = checksum 'GB000263494'</lang>
Java
This now assumes that the existing Luhn algorithm implementation from the Luhn test of credit card numbers task is available in the same (default) package.
<lang java>public class ISIN {
public static void main(String[] args) {
String[] isins = {
"US0378331005",
"US0373831005",
"U50378331005",
"US03378331005",
"AU0000XVGZA3",
"AU0000VXGZA3",
"FR0000988040",
};
for (String isin : isins)
System.out.printf("%s is %s%n\n", isin, ISINtest(isin) ? "valid" : "not valid");
}
static boolean ISINtest(String isin) {
isin = isin.trim().toUpperCase();
if (!isin.matches("^[A-Z]{2}[A-Z0-9]{9}\\d$"))
return false;
StringBuilder sb = new StringBuilder();
for (char c : isin.substring(0, 12).toCharArray())
sb.append(Character.digit(c, 36));
return Luhn.luhnTest(sb.toString()); }
}</lang>
US0378331005 is valid US0373831009 is valid D56000543287 is not valid AU0000XVGZA3 is valid AU0000VXGZA3 is valid GB0002634946 is valid US0373831005 is not valid
Kotlin
As the Luhn test method is only a few lines, it's reproduced here for convenience: <lang scala>// version 1.1
object Isin {
val r = Regex("^[A-Z]{2}[A-Z0-9]{9}[0-9]$")
fun isValid(s: String): Boolean {
// check format
if (!s.matches(r)) return false
// validate checksum
val sb = StringBuilder()
for (c in s) {
when (c) {
in '0'..'9' -> sb.append(c)
in 'A'..'Z' -> sb.append((c.toInt() - 55).toString().padStart(2, '0'))
}
}
return luhn(sb.toString())
}
private fun luhn(s: String): Boolean {
fun sumDigits(n: Int) = n / 10 + n % 10
val t = s.reversed()
val s1 = t.filterIndexed { i, _ -> i % 2 == 0 }.sumBy { it - '0' }
val s2 = t.filterIndexed { i, _ -> i % 2 == 1 }.map { sumDigits((it - '0') * 2) }.sum()
return (s1 + s2) % 10 == 0
}
}
fun main(args: Array<String>) {
val isins = arrayOf(
"US0378331005", "US0373831005", "U50378331005", "US03378331005",
"AU0000XVGZA3", "AU0000VXGZA3", "FR0000988040"
)
for (isin in isins) {
println("$isin\t -> ${if (Isin.isValid(isin)) "valid" else "not valid"}")
}
}</lang>
- Output:
US0378331005 -> valid US0373831005 -> not valid U50378331005 -> not valid US03378331005 -> not valid AU0000XVGZA3 -> valid AU0000VXGZA3 -> valid FR0000988040 -> valid
Lua
<lang Lua>function luhn (n)
local revStr, s1, s2, digit, mod = n:reverse(), 0, 0
for pos = 1, #revStr do
digit = tonumber(revStr:sub(pos, pos))
if pos % 2 == 1 then
s1 = s1 + digit
else
digit = digit * 2
if digit > 9 then
mod = digit % 10
digit = mod + ((digit - mod) / 10)
end
s2 = s2 + digit
end
end
return (s1 + s2) % 10 == 0
end
function checkISIN (inStr)
if #inStr ~= 12 then return false end
local numStr = ""
for pos = 1, #inStr do
numStr = numStr .. tonumber(inStr:sub(pos, pos), 36)
end
return luhn(numStr)
end
local testCases = {
"US0378331005", "US0373831005", "US0373831005", "US03378331005", "AU0000XVGZA3", "AU0000VXGZA3", "FR0000988040"
} for _, ISIN in pairs(testCases) do print(ISIN, checkISIN(ISIN)) end</lang>
- Output:
US0378331005 true US0373831005 false US0373831005 false US03378331005 false AU0000XVGZA3 true AU0000VXGZA3 true FR0000988040 true
Perl
We reuse the luhn_test() function from Luhn test of credit card numbers#Perl. <lang perl>use strict; use English; use POSIX; use Test::Simple tests => 7;
ok( validate_isin('US0378331005'), 'Test 1'); ok( ! validate_isin('US0373831005'), 'Test 2'); ok( ! validate_isin('U50378331005'), 'Test 3'); ok( ! validate_isin('US03378331005'), 'Test 4'); ok( validate_isin('AU0000XVGZA3'), 'Test 5'); ok( validate_isin('AU0000VXGZA3'), 'Test 6'); ok( validate_isin('FR0000988040'), 'Test 7'); exit 0;
sub validate_isin {
my $isin = shift;
$isin =~ /\A[A-Z]{2}[A-Z\d]{9}\d\z/s or return 0;
my $base10 = join(q{}, map {scalar(POSIX::strtol($ARG, 36))}
split(//s, $isin));
return luhn_test($base10);
}</lang>
- Output:
1..7 ok 1 - Test 1 ok 2 - Test 2 ok 3 - Test 3 ok 4 - Test 4 ok 5 - Test 5 ok 6 - Test 6 ok 7 - Test 7
Perl 6
Using the luhn-test function defined at Luhn test of credit card numbers#Perl 6:
<lang perl6>my $ISIN = /
^ <[A..Z]>**2 <[A..Z0..9]>**9 <[0..9]> $
<?{ luhn-test $/.comb.map({ :36($_) }).join }>
/;</lang>
Testing:
<lang perl6>say "$_ is {$ISIN ?? "valid" !! "not valid"}" for < US0378331005 US0373831005 U50378331005 US03378331005 AU0000XVGZA3 AU0000VXGZA3 FR0000988040 >;</lang>
- Output:
US0378331005 is valid US0373831005 is not valid U50378331005 is not valid US03378331005 is not valid AU0000XVGZA3 is valid AU0000VXGZA3 is valid FR0000988040 is valid
Phix
Note this (slightly better) version of Luhn() has the reverse() inside it, whereas the original did not. <lang Phix>function Luhn(string st) integer s=0, d
st = reverse(st)
for i=1 to length(st) do
d = st[i]-'0'
s += iff(mod(i,2)?d,d*2-(d>4)*9)
end for
return remainder(s,10)=0
end function
function valid_ISIN(string st) -- returns 1 if valid, else 0/2/3/4. -- (feel free to return 0 instead of 2/3/4)
if length(st)!=12 then return 2 end if
for i=length(st) to 1 by -1 do
integer ch = st[i]
if ch>='A' then
if ch>'Z' then return 3 end if
st[i..i] = sprintf("%d",ch-55)
elsif i<=2 then
return 4
elsif ch<'0' or ch>'9' then
return 3
end if
end for
return Luhn(st)
end function
sequence tests = {"US0378331005", -- valid
"US0373831005", -- not valid The transposition typo is caught by the checksum constraint.
"U50378331005", -- not valid The substitution typo is caught by the format constraint.
"US03378331005", -- not valid The duplication typo is caught by the format constraint.
"AU0000XVGZA3", -- valid
"AU0000VXGZA3", -- valid Unfortunately, not all transposition typos are caught by the checksum constraint.
"FR0000988040"} -- valid
constant reasons = {"wrong checksum","valid","wrong length","bad char","wrong country"}
for i=1 to length(tests) do
string ti = tests[i]
printf(1,"%s : %s\n",{ti,reasons[valid_ISIN(ti)+1]})
end for</lang>
- Output:
US0378331005 : valid US0373831005 : wrong checksum U50378331005 : wrong country US03378331005 : wrong length AU0000XVGZA3 : valid AU0000VXGZA3 : valid FR0000988040 : valid
PowerShell
<lang PowerShell> function Test-ISIN {
[CmdletBinding()]
[OutputType([bool])]
Param
(
[Parameter(Mandatory=$true, Position=0)]
[ValidatePattern("[A-Z]{2}\w{9}\d")]
[ValidateScript({$_.Length -eq 12})]
[string]
$Number
)
function Split-Array
{
$array = @(), @()
$input | ForEach-Object {$array[($index = -not $index)] += $_}
$array[1], $array[0]
}
filter ConvertTo-Digit
{
if ($_ -gt 9)
{
$_.ToString().ToCharArray() | ForEach-Object -Begin {$n = 0} -Process {$n += [Char]::GetNumericValue($_)} -End {$n}
}
else
{
$_
}
}
$checkDigit = $Number[-1]
$digits = ($Number -replace ".$").ToCharArray() | ForEach-Object {
if ([Char]::IsDigit($_))
{
[Char]::GetNumericValue($_)
}
else
{
[int][char]$_ - 55
}
}
$odds, $evens = ($digits -join "").ToCharArray() | Split-Array
if ($odds.Count -gt $evens.Count)
{
$odds = $odds | ForEach-Object {[Char]::GetNumericValue($_) * 2} | ConvertTo-Digit
$evens = $evens | ForEach-Object {[Char]::GetNumericValue($_)}
}
else
{
$odds = $odds | ForEach-Object {[Char]::GetNumericValue($_)}
$evens = $evens | ForEach-Object {[Char]::GetNumericValue($_) * 2} | ConvertTo-Digit
}
$sum = ($odds | Measure-Object -Sum).Sum + ($evens | Measure-Object -Sum).Sum
(10 - ($sum % 10)) % 10 -match $checkDigit
} </lang> <lang PowerShell> "US0378331005","US0373831005","US0337833103","AU0000XVGZA3","AU0000VXGZA3","FR0000988040" | ForEach-Object {
[PSCustomObject]@{
ISIN = $_
IsValid = Test-ISIN -Number $_
}
} </lang>
- Output:
ISIN IsValid ---- ------- US0378331005 True US0373831005 False US0337833103 False AU0000XVGZA3 True AU0000VXGZA3 True FR0000988040 True
PureBasic
<lang PureBasic>EnableExplicit
Procedure.b Check_ISIN(*c.Character)
Define count.i=0, Idx.i=1, v.i=0, i.i
Dim s.i(24)
If MemoryStringLength(*c) > 12 : ProcedureReturn #False : EndIf
While *c\c
count+1
If *c\c>='0' And *c\c<='9'
If count<=2 : ProcedureReturn #False : EndIf
s(Idx)= *c\c - '0'
Idx+1
ElseIf *c\c>='A' And *c\c<='Z'
s(Idx)= (*c\c - ('A'-10)) / 10
Idx+1
s(Idx)= (*c\c - ('A'-10)) % 10
Idx+1
Else
ProcedureReturn #False
EndIf
*c + SizeOf(Character)
Wend
For i=Idx-2 To 0 Step -2
If s(i)*2 > 9
v+ s(i)*2 -9
Else
v+ s(i)*2
EndIf
v+s(i+1)
Next
ProcedureReturn Bool(v%10=0)
EndProcedure
Define.s s OpenConsole("Validate_International_Securities_Identification_Number (ISIN)")
If ReadFile(0,"c:\code_pb\rosettacode\data\isin.txt")
While Not Eof(0)
s=ReadString(0)
Print(s+~"\t")
If Check_ISIN(@s) : PrintN("TRUE") : Else : PrintN("FALSE") : EndIf
Wend
CloseFile(0)
EndIf Input()</lang>
- Output:
US0378331005 TRUE US0373831005 FALSE U50378331005 FALSE US03378331005 FALSE AU0000XVGZA3 TRUE AU0000VXGZA3 TRUE FR0000988040 TRUE
Python
<lang python>def check_isin(a):
if len(a) != 12 or not all(c.isalpha() for c in a[:2]) or not all(c.isalnum() for c in a[2:]):
return False
s = "".join(str(int(c, 36)) for c in a)
return 0 == (sum(sum(divmod(2 * (ord(c) - 48), 10)) for c in s[-2::-2]) +
sum(ord(c) - 48 for c in s[::-2])) % 10
- A more readable version
def check_isin_alt(a):
if len(a) != 12:
return False
s = []
for i, c in enumerate(a):
if c.isdigit():
if i < 2:
return False
s.append(ord(c) - 48)
elif c.isupper():
if i == 11:
return False
s += divmod(ord(c) - 55, 10)
else:
return False
v = sum(s[::-2])
for k in s[-2::-2]:
k = 2 * k
v += k - 9 if k > 9 else k
return v % 10 == 0
[check_isin(s) for s in ["US0378331005", "US0373831005", "U50378331005", "US03378331005",
"AU0000XVGZA3", "AU0000VXGZA3", "FR0000988040"]]
- [True, False, False, False, True, True, True]</lang>
Racket
<lang racket>
- lang racket
- convert a base36 character (#\0 - #\Z) to its equivalent
- in base 10 as a string ("0" - "35")
(define (base36-char->base10-string c)
(let ([char-int (char->integer (char-upcase c))]
[zero-int (char->integer #\0)]
[nine-int (char->integer #\9)]
[A-int (char->integer #\A)]
[Z-int (char->integer #\Z)])
(cond [(and (>= char-int zero-int) (<= char-int nine-int)) (~a c)]
[(and (>= char-int A-int) (<= char-int Z-int)) (~a (+ (- char-int A-int) 10))]
[else null])))
- substitute equivalent base 10 numbers for base 36 characters in string
- this is a character-by-character substitution not a conversion
- of a base36 number to a base10 number
(define (base36-string-characters->base10-string-characters s)
(for/fold ([joined ""])
([tenstr (map base36-char->base10-string (string->list (string-upcase s)))])
(values (string-append joined tenstr))))
- This uses the Racket Luhn solution
(define [isin-test? s]
(let ([RE (pregexp "^[A-Z]{2}[A-Z0-9]{9}[0-9]{1}$")])
(and
(regexp-match? RE s)
(luhn-test (string->number (base36-string-characters->base10-string-characters s))))))
(define test-cases '("US0378331005" "US0373831005" "U50378331005" "US03378331005" "AU0000XVGZA3" "AU0000VXGZA3" "FR0000988040"))
(map isin-test? test-cases)
- -> '(#t #f #f #f #t #t #t)
</lang>
- Output:
'(#t #f #f #f #t #t #t)
REXX
<lang rexx>/*REXX program validates the checksum digit for an International Securities ID number.*/ parse arg z /*obtain optional ISINs from the C.L.*/ if z= then z= "US0378331005 US0373831005 U50378331005 US03378331005 AU0000XVGZA3" ,
'AU0000VXGZA3 FR0000988040' /* [↑] use the default list of ISINs.*/
/* [↓] process all specified ISINs.*/
do n=1 for words(z); x=word(z, n); y=x /*obtain an ISIN from the Z list. */
$= /* [↓] construct list of ISIN digits. */
do k=1 for length(x); _=substr(x,k,1) /*the ISIN may contain alphabetic chars*/
p=pos(_, '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ') /*X must contain A──►Z, 0──►9.*/
if p==0 then y= /*trigger "not" valid below.*/
else $=$ || p-1 /*convert X string (base 36 ──► dec).*/
end /*k*/ /* [↑] convert alphabetic ──► digits.*/
@= /*placeholder for the "not" in message.*/
if length(y)\==12 then @= "not" /*check if the ISIN is exactly 12 chars*/
if \datatype( left(x,2),'U') then @= "not" /* " " " " 1st 2 chars cap let*/
if \datatype(right(x,1),'W') then @= "not" /* " " " " last char not digit*/
if @== then if \luhn($) then @= "not" /* " " " " passed Luhn test. */
say right(x,30) right(@, 5) "valid" /*display the yea or nay message.*/
end /*n*/ /* [↑] 1st 3 IFs could've been combined*/
exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ Luhn: procedure; parse arg x; $=0 /*get credit card number; zero $ sum. */
y=reverse(left(0, length(x) // 2)x) /*add leading zero if needed, & reverse*/
do j=1 to length(y)-1 by 2; _=2 * substr(y, j+1, 1)
$=$ + substr(y, j, 1) + left(_, 1) + substr(_, 2 , 1, 0)
end /*j*/ /* [↑] sum the odd and even digits.*/
return right($, 1)==0 /*return "1" if number passed Luhn test*/</lang>
output when using the defaults for input:
US0378331005 valid
US0373831005 not valid
U50378331005 not valid
US03378331005 not valid
AU0000XVGZA3 valid
AU0000VXGZA3 valid
FR0000988040 valid
Ruby
Using a pre-existing luhn method: <lang ruby>RE = /\A[A-Z]{2}[A-Z0-9]{9}[0-9]{1}\z/
def valid_isin?(str)
return false unless str =~ RE
luhn(str.chars.map{|c| c.to_i(36)}.join)
end
p %w(US0378331005 US0373831005 U50378331005 US03378331005 AU0000XVGZA3 AU0000VXGZA3 FR0000988040).map{|tc| valid_isin?(tc) }
- => [true, false, false, false, true, true, true]</lang>
SAS
<lang sas>data test; length isin $20 ok $1; input isin; keep isin ok; array s{24}; link isin; return; isin: ok="N"; n=length(isin); if n=12 then do;
j=0;
do i=1 to n;
k=rank(substr(isin,i,1));
if k>=48 & k<=57 then do;
if i<3 then return;
j+1;
s{j}=k-48;
end;
else if k>=65 & k<=90 then do;
if i=12 then return;
k+-55;
j+1;
s{j}=int(k/10);
j+1;
s{j}=mod(k,10);
end;
else return;
end;
v=sum(of s{*});
do i=j-1 to 1 by -2;
v+s{i}-9*(s{i}>4);
end;
if mod(v,10)=0 then ok="Y"; end; return; cards; US0378331005 US0373831005 U50378331005 US03378331005 AU0000XVGZA3 AU0000VXGZA3 FR0000988040
run;</lang>
Tcl
<lang Tcl>package require Tcl 8.6 ;# mostly needed for [assert]. Substitute a simpler one or a NOP if required.</lang>
A proc like assert is always good to have around. This one tries to report values used in its expression using subst:
<lang Tcl>proc assert {expr} { ;# for "static" assertions that throw nice errors
if {![uplevel 1 [list expr $expr]]} {
set msg "{$expr}"
catch {append msg " {[uplevel 1 [list subst -noc $expr]]}"}
tailcall throw {ASSERT ERROR} $msg
}
}</lang>
isin itself is a simple package. We compute the alphabet when the package is loaded in _init, because that's more fun than typing out the table:
<lang Tcl>namespace eval isin {
proc _init {} { ;# sets up the map used on every call
variable map
set alphabet abcdefghijklmnopqrstuvwxyz
set n 9
lmap c [split $alphabet ""] {
lappend map $c [incr n]
}
}
_init
proc normalize {isin} {
variable map
string map $map [string tolower [string trim $isin]]
}
# copied from "Luhn test of credit card numbers"
# included here for ease of testing, and because it is short
proc luhn digitString {
if {[regexp {[^0-9]} $digitString]} {error "not a number"}
set sum 0
set flip 1
foreach ch [lreverse [split $digitString {}]] {
incr sum [lindex {
{0 1 2 3 4 5 6 7 8 9}
{0 2 4 6 8 1 3 5 7 9}
} [expr {[incr flip] & 1}] $ch]
}
return [expr {($sum % 10) == 0}]
}
proc validate {isin} {
if {![regexp {^[A-Z]{2}[A-Z0-9]{9}[0-9]$} $isin]} {return false}
luhn [normalize $isin]
}
}</lang>
To run the test suite, we use the tcltest framework included with Tcl:
<lang Tcl>package require tcltest
tcltest::test isin-1 "Test isin validation" -body {
foreach {isin ok} {
US0378331005 yes
US0373831005 no
U50378331005 no
US03378331005 no
AU0000XVGZA3 yes
AU0000VXGZA3 yes
FR0000988040 yes
} {
if {$ok} {
assert {[isin::validate $isin]}
} else {
assert {![isin::validate $isin]}
}
}
return ok
} -result ok</lang>
Visual Basic
<lang vb> Option Explicit
Function MakeIsinCode(Exchange As String, security As String)
Dim numLeadingZeroes As Integer numLeadingZeroes = 9 - Len(security) Dim leader As String leader = Exchange & String(numLeadingZeroes, "0") & security MakeIsinCode = leader & CStr(IsinCheckDigit(leader))
End Function
Function IsinCheckDigit(ByVal security As String) As Integer
Dim digits As String
Dim i As Integer
For i = 1 To Len(security)
Dim ch As String
ch = UCase(Mid(security, i, 1))
If ch >= "A" And ch <= "Z" Then
' A to Z translated to "10", "11", .. "35"
digits = digits & CStr(Asc(ch) - 55)
ElseIf ch >= "0" And ch <= "9" Then
digits = digits & ch
Else
Err.Raise 50001, , "Security must contain only letters and digits"
End If
Next
Dim total As Integer
Dim tmp As Integer
total = 0
'If rightmost even, "other" digits for doubling are 2,4,6. If rightmost odd, they're 1,3,5.
'rightmost digit is always doubled, so start with it and work backwards
Dim other As Boolean
other = True
For i = Len(digits) To 1 Step -1
tmp = CInt(Mid(digits, i, 1))
If other Then
If tmp < 5 Then
' 0 to 4 map to 0,2,4,6,8
total = total + (tmp * 2)
Else
' 5 to 9 map to 1,3,5,7,9
total = total + ((tmp * 2) - 9)
End If
Else
total = total + tmp
End If
'Toggle doubling flag
other = Not other
Next
'Last Mod 10 is to wrap 10 to zero
IsinCheckDigit = (10 - (total Mod 10)) Mod 10
End Function </lang>
zkl
Uses the luhn test from Luhn_test_of_credit_card_numbers#zkl (copied here as it is short). <lang zkl>fcn validateISIN(isin){
RegExp(String("^","[A-Z]"*2,"[A-Z0-9]"*9,"[0-9]$")).matches(isin) and
luhnTest(isin.split("").apply("toInt",36).concat().toInt())
} fcn luhnTest(n){
0 == (n.split().reverse().reduce(fcn(s,n,clk){
s + if(clk.inc()%2) n else 2*n%10 + n/5 },0,Ref(1)) %10)
}</lang> <lang zkl>println(" ISIN Valid?"); foreach isin in (T("US0378331005","US0373831005","U50378331005", "US03378331005","AU0000XVGZA3","AU0000VXGZA3","FR0000988040")){
println(isin," --> ",validateISIN(isin));
}</lang>
- Output:
ISIN Valid? US0378331005 --> True US0373831005 --> False U50378331005 --> False US03378331005 --> False AU0000XVGZA3 --> True AU0000VXGZA3 --> True FR0000988040 --> True
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