short hand for using if statement for single variable over and over again

Question

My question is pretty simple.

Is there a short hand for

if (a == "p" || a == "l" || a == "g" || a == "z")
{
            //do something 
}

Is there an alternate to this. Meaning, Can I just do something like

if (a == ("p" || "l" || "g" || "z"))//this doesn't work

Similar to all the other questions about this, the answer is: no. — Oliver Charlesworth, Aug 30 '13 at 18:54
What language is this? It looks like C/C++, but one can never be sure with such a small clip. — SethMMorton, Aug 30 '13 at 18:54
Was asked many times before e.g. http://stackoverflow.com/questions/18347033/how-to-shorten-my-conditional-statements - this is JavaScript, but concept is similar — Yuriy Galanter, Aug 30 '13 at 18:57

Tim S. · Accepted Answer · 2013-08-30T19:04:52.157

5

if (new[] { "p", "l", "g", "z" }.Contains(a))

If performance might be a concern, e.g. you have a large list of strings to check, or check it frequently, you should consider storing them in a HashSet<string>, e.g.

var mySet = new HashSet<string> { "p", "l", "g", "z" };
// later...
if (mySet.Contains(a))

edited Aug 30 '13 at 19:04

answered Aug 30 '13 at 18:58

Tim S.

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+1. usual reminder - very readable option for short list, consider `HashSet`/`Dictionary` if list is long/frequently used code. – Alexei Levenkov Aug 30 '13 at 19:01

score 1 · Answer 2 · answered Aug 30 '13 at 18:55

1

Arrays.asList(new String[]{"a","b","c"}).contains("b");

answered Aug 30 '13 at 18:55

Ashish Thukral

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That looks like Java, this is C# (probably wasn't clear when you wrote that). – Tim S. Aug 30 '13 at 18:57
1

oh, you didn't mention in your post initially, being a Java developer that is what comes to my mind first. – Ashish Thukral Aug 30 '13 at 19:00

score 1 · Answer 3 · answered Aug 30 '13 at 19:01

1

C# code

var myList = new[] { "p", "l", "g", "z" };

if(myList.Contains(a))
{
 //victory :)
}

answered Aug 30 '13 at 19:01

Johan

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score 1 · Answer 4 · answered Aug 30 '13 at 19:02

1

You can use switch statement with fall thru:

switch (a) {

  case "p":
  case "l":
  case "g":
  case "z":
    // do something
}

answered Aug 30 '13 at 19:02

Yuriy Galanter

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My apologies, do use other answers, they're much much shorter – Yuriy Galanter Aug 30 '13 at 19:06

score 1 · Answer 5 · answered Aug 30 '13 at 19:03

Better if you write an extension method like:

public static class MyExtension
{
    public static bool In(this string c, params string[] items)
    {
         return items.Contains(c);
         //OR //return items.Any(r => r == c);
    }
}

and then use it like:

if ("a".In("p", "l", "a", "z"))
{
    Console.WriteLine("Exists");
}
else
{
    Console.WriteLine("Doesn't exist");
}

short hand for using if statement for single variable over and over again

5 Answers5