Dictionary Key look up with variable length inputs

I am decoding GS1 barcodes and need to match up application identifiers with relevant data about them.

00 SSCC (Serial Shipping Container Code) N2+N18 FALSE SSCC
01 Global Trade Item Number (GTIN) N2+N14 FALSE GTIN
02 GTIN of Contained Trade Items N2+N14 FALSE CONTENT
10 Batch or Lot Number N2+X.20 TRUE BATCH/LOT
11 Production Date (YYMMDD) N2+N6 FALSE PROD DATE
12 Due Date (YYMMDD) N2+N6 FALSE DUE DATE
13 Packaging Date (YYMMDD) N2+N6 FALSE PACK DATE
15 Best Before Date (YYMMDD) N2+N6 FALSE BEST BEFORE or BEST BY
16 Sell By Date (YYMMDD) N2+N6 FALSE SELL BY
17 Expiration Date (YYMMDD) N2+N6 FALSE USE BY OR EXPIRY
20 Variant Number N2+N2 FALSE VARIANT
21 Serial Number N2+X.20 TRUE SERIAL
240 Additional Item Identification N3+X.30 TRUE ADDITIONAL ID
241 Customer Part Number N3+X.30 TRUE CUST. PART NO.
242 Made-to-Order Variation Number N3+N.6 TRUE MTO VARIANT
243 Packaging Component Number N3+X.20 TRUE PCN
250 Secondary Serial Number N3+X.30 TRUE SECONDARY SERIAL
251 Reference to Source Entity N3+X.30 TRUE REF. TO SOURCE
253 Global Document Type Identifier (GDTI) N3+N13+XTRUE GDTI
254 GLN Extension Component N3+X.20 TRUE GLN EXTENSION COMPONENT
255 Global Coupon Number (GCN) N3+N13+NTRUE GCN
30 Count of Items (Variable Measu ... N2+N..8 TRUE VAR. COUNT
3100 Net weight kilograms (Var... ) N4+N6 FALSE NET WEIGHT (kg)
...


Full list here.

This is how I identify them:

`public Dictionary> gs1AiDict { get; private set; }

var aiDataOut = new Tuple("","",false,"");

//Get first 4 digits (max identifier leng

Code duplication is a sin

You could use shorter and more readable code using a simple for loop:

int applicationIdentifier = Convert.ToInt16(pi.Substring(1,4));
for (int i = 100; i >= 1; i /= 10)
{
    int maybeId = applicationIdentifier / i;
    if (gs1AiDict.TryGetValue(maybeId, out aiDataOut))
    {
        id = aiDataOut.Item1;
        format = aiDataOut.Item2;
        func = aiDataOut.Item3;
        abrv = aiDataOut.Item4;
        return;
    }
}   
Console.WriteLine("No Application Identifier found!");

You should also consider making your data object something along the lines of a Dicitionary, that 4-member tuple doesn't help readibility. Then you could also return an ApplicationInfo object instead of copying the fields to local variables.

StackExchange Code Review Q#70095, answer score: 3