Question

If I have 2 lists of strings:

List<string> firstList = new List<string>("010", "111", "123");
List<string> secondList = new List<string>("010", "111", "999");

How can I compare each individual character in each item from the lists? Ex: Should compare “0” with “0”, “1” with “1”, “0” with “0” and so on. It appears that I can use SelectMany but I am stuck on how to do it

EDIT:

These lists should return true when compared with each other (as asterisk means any character and I am validating to ensure that each item is exactly 3 chars in length)

List<string> firstList = new List<string>("010", "111", "123");
List<string> secondList = new List<string>("010", "1*1", "***");

Answer 1

If you just want to compare for a matching character sequence between your lists:

bool sameCharacters = Enumerable.SequenceEqual(firstList.SelectMany(x => x), 
                                               secondList.SelectMany(x => x));

This would result in true, i.e. for the following two lists – their character sequences match ("010111123" for both), their individual string entries do not:

List<string> firstList = new List<string> {"010", "111", "123" };
List<string> secondList = new List<string> {"010", "11", "1123" };

Edit in response to comments:

For a wildcard match you could use Zip() and compare each character, return true if they match based on wildcard conditions, then just check that each element in the zipped sequence is true.

var isWildCardMatch = firstList.SelectMany(x => x).Zip(secondList.SelectMany( x => x),
(a,b) =>
{
if(a==b || a ==’‘ || b == ‘‘)
return true;
return false;

    }).All( x=> x);

Above approach crossed string entry boundaries, which would cause false matches – here a better approach:

bool isWildCardMatch = firstList.Zip(secondList, (x, y) =>
{
    var matchWord = y.Select((c, i) => c == '*' ? x[i] : c);
    return matchWord.SequenceEqual(x);
}).All(x => x);