How to compare to list of date in C#? [duplicate]

Question

I have two list of date. I have to compare both list and find missing date. My first list looks like this:

2015-07-21
2015-07-22
2015-07-23
2015-07-24
2015-07-25
2015-07-26
2015-07-27

My second list looks like this

2015-07-21
2015-07-22
2015-07-23
2015-07-25
2015-07-26
2015-07-27

I have to find the missing date between the two list :

I tried this

var anyOfthem = firstList.Except(secondList);

But it didn't work. Can anyone help me with this ?

Answer 1

Well, you could use .Except() and .Union() methods :

        string[] array1 = 
        {
        "2015-07-21",
        "2015-07-22",
        "2015-07-23",
        "2015-07-24",
        "2015-07-25",
        "2015-07-26",            
        };

        string[] array2 = 
        {
        "2015-07-21",
        "2015-07-22",
        "2015-07-23",            
        "2015-07-25",
        "2015-07-26",
        "2015-07-27"
        };

        var result = array1.Except(array2).Union(array2.Except(array1));

        foreach (var item in result) 
        {
           Console.WriteLine(item);
        }

Output : "2015-07-24", "2015-07-27",

Answer 2

string[] array1 = 
{
    "2015-07-21",
    "2015-07-22",
    "2015-07-23",
    "2015-07-24",
    "2015-07-25",
    "2015-07-26",            
};

string[] array2 = 
{
    "2015-07-21",
    "2015-07-22",
    "2015-07-23",            
    "2015-07-25",
    "2015-07-26",
    "2015-07-27"
};

var common = list1.Intersect(list2);
var anyOfThem = list1.Except(common).Concat(list2.Except(common));

foreach (var date in anyOfThem)
    Console.WriteLine(date);

// 2015-07-24
// 2015-07-27