Luhn test of credit card numbers: Difference between revisions

=={{header|Excel}}==

===LAMBDA===

Binding the name '''luhnChecked''' to the following lambda expression in the Name Manager of the Excel WorkBook:

(See [https://www.microsoft.com/en-us/research/blog/lambda-the-ultimatae-excel-worksheet-function/ LAMBDA: The ultimate Excel worksheet function])

{{Works with|Office 365 betas 2021}}

<lang lisp>luhnChecked

=LAMBDA(s,

LET(

ns, REVERSECOLS(VALUE(CHARSROW(s))),

ixs, SEQUENCE(1, COLUMNS(ns), 1, 1),

0 = MOD(SUM(

FILTER(ns, 0 <> MOD(ixs, 2))

) + (

LAMBDA(n,

DIGITSUM(

CONCAT(TEXT(2 * n, "0"))

)

)(

FILTER(ns, 0 = MOD(ixs, 2))

)

),

10

)

)

)</lang>

and also assuming the following generic bindings in the Name Manager for the WorkBook:

<lang lisp>CHARSROW

=LAMBDA(s,

MID(s,

SEQUENCE(1, LEN(s), 1, 1),

1

)

)

DIGITSUM

=LAMBDA(s,

SUM(VALUE(

MID(s,

SEQUENCE(LEN(s), 1, 1, 1),

1

)

))

)

REVERSECOLS

=LAMBDA(xs,

LET(

n, COLUMNS(xs),

SORTBY(

xs,

SEQUENCE(1, n, n, -1)

)

)

)</lang>

{{Out}}

{| class="wikitable"

|-

|||style="text-align:right; font-family:serif; font-style:italic; font-size:120%;"|fx

! colspan="2" style="text-align:left; vertical-align: bottom; font-family:Arial, Helvetica, sans-serif !important;"|=luhnChecked(A2)

|- style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff;"

|

| A

| B

|-

| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 1

| style="font-weight:bold" | Digit strings

| style="font-weight:bold" | Luhn result

|-

| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 2

| style="text-align:right" | 49927398716

| style="background-color:#cbcefb" | TRUE

|-

| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 3

| style="text-align:right" | 49927398717

| FALSE

|-

| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 4

| style="text-align:right" | 1234567812345678

| FALSE

|-

| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 5

| style="text-align:right" | 1234567812345670

| TRUE

|}