Compare All Strings in a List - C#

Question

I have List<String> clr9, which has a known Count of nine.

What I want to know is how to shorthand something that goes on later in the code.

else if(clr9[0].Equals(clr9[1]) && clr9[0].Equals(clr9[2]) && clr9[0].Equals(clr9[3]))

I've already tried this:

else if(clr9[0].Equals(clr9[1].Equals(clr9[2].Equals(clr9[3]))))

but it doesn't seem to work. Is there any way I can avoid the ampersands? Basically just asking if there's a way to find out if all 4 strings are the same without cluttering up that if statement.

I might need to add that the numbers next to the clrs dictate their capacity. so clr9 would have 9 items in it. I'm only checking if the first 4 are the same. Not the entire list. — Chamkey
– Chamkey, Commented Mar 29, 2017 at 2:59
@Chamkey you don't need to check the capacity, distincting will work for any length of list — Eamonn McEvoy
– Eamonn McEvoy, Commented Mar 29, 2017 at 6:36

Marc L. · Accepted Answer · 2017-03-29 02:50:43Z

1

Distinct will work, but I think testing equality directly is more expressive of intent:

if(clr9.Skip(1).All(c => c.Equals(clr9[0])))

answered Mar 29, 2017 at 2:50

Marc L.

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2 Comments

Millie Smith Over a year ago

I upvoted as I think this is the best solution so far, but I would use c == clr9[0] instead.

Marc L. Over a year ago

For String I tend to use Equals(String). It's more verbose, in this case perhaps more cluttered than the equality operator. But for String I prefer the syntactical affinity with Equals(String, StringComparison) to the prettier ==.

Eamonn McEvoy · Accepted Answer · 2017-03-29 06:40:07Z

1

You could distinct the list to remove duplicates and check the length.

e.g.

clr9.Distinct().Count() == 1

or, if you want it to be case insensitive

clr9.Distinct(StringComparer.CurrentCultureIgnoreCase).Count() == 1

edited Mar 29, 2017 at 6:40

answered Mar 29, 2017 at 2:48

Eamonn McEvoy

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Comments

mindOfAi · Accepted Answer · 2017-03-29 02:47:16Z

0

Well, if you're only checking all the strings inside a single list like for example clr9. What you can do is use LINQ Distinct:

if (clr9.Distinct().Skip(1).Any())
{
  //Do something
}

T

Hope it helps!

answered Mar 29, 2017 at 2:47

mindOfAi

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Comments

Daniel Bernsons · Accepted Answer · 2017-03-29 03:03:45Z

0

I've come across this situation often enough that I've written a simple extension method for it.

public static bool In<T>(this T val, params T[] options)
{
    return options.Contains(val);
}

And then to use it in your code statement

else if (clr9[0].In(clr9.Skip(1).ToArray()))

Edit based on comment by OP, this works just as well:

else if (clr9[0].In(clr9[1], clr9[2], clr9[3]))

Or

else if (clr9[0].In(clr9.Skip(1).Take(3).ToArray())

edited Mar 29, 2017 at 3:03

answered Mar 29, 2017 at 2:51

Daniel Bernsons

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1 Comment

Kenneth K. Over a year ago

object?!?!?! Why not make the method generic?

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