I have a function like this(foo): I need to compare the input string and perform a task accordingly . Task is same, but only for a selected set of values. For all other values do nothing.
function foo(string x)
{
if(x == "abc")
//do Task1
if(x == "efg")
//do Task1
if(x == "hij")
//do Task1
if(x == "lmn")
//do Task1
}
Is there any other means to do checking other than this? Or putting OR operator inside if?
What is the preferred way?
There are many ways of doing it. One would be as follows:
var target = new HashSet<string>{ "abc", "efg", "lmn" };
if (target.Contains(x)) {
...
}
At max [my list of strings] can grow to 50 strings which is a rare possibility.
Then you should make target a static readonly in your class, like this:
private static readonly StringTargets = new HashSet<string>{ "abc", "efg", "lmn" };
Doing so would ensure that the set is created only once, and is not re-created each time the execution goes through the method that uses it.
if than the switch, with the switch you are still pretty much writing the same amount of code.
target into some class or provider and do if(BusinessRulesFooClass.Something(x)). In fact, depending on the scenario it's possible it should have been like that all along...
static variable, it needs to be defined outside of the method, and its declaration may not use var. Copy-paste the second code snippet from the answer outside your method, and it should work. I assume that you have using System.Collections.Generic; at the top of your file, too.do it like this
function foo(string x)
{
switch(x)
{
case "abc":
case "efg":
case "hij":
case "lmn":
{
//do task 1
break;
}
default:
break;
}
}
Alternatively you can do this
if(x == "abc"||x == "efg"||x == "hij"||x == "lmn")
//do Task1
One way would be to make an array of the acceptable strings, then see if that array contains x
function foo(string x)
{
string[] strings = new string[] {"abc", "efg", "hij", "lmn"};
if (strings.contains(x)){
//do task 1
}
}
You can use a switch statement with a default value to catch anything that didn't match
http://blogs.msdn.com/b/brada/archive/2003/08/14/50227.aspx
function foo(string x) {
switch(x) {
case "abc":
//do task 1
break;
case "efg":
//do task 2
break;
default:
//all other cases
break;
}
}
switchstatement is a good fit for such cases; it allows you to write the target values nicely separated and with a minimum of unnecessary boilerplate.if (new[] {"abc", "efg", "hij", "lmn"}.Contains(x)) { Task1(); }... Not sure myself, but it works.string[]does not actually contain a methodContains, so that works only because of Linq. Not that that is a problem. The pure array solution would beif (Array.IndexOf(new[] {"abc", "efg", "hij", "lmn"}, x) != -1) { ... }, but that looks quite awful.if(x.Is("abc", "efg", "hij", "lmn")) { }