Linq query: does this array contain this string?

Question

Is there a better way to do this?

    public bool IsServiceRunning(string serviceName)
    {
        string[] services =  client.AllServices();
        return (from s in services
                where s.Equals(serviceName, StringComparison.InvariantCultureIgnoreCase)
                select s).Count() > 0;
    }

The case insensitivity in the compare is important.

How that is more clear than a simple foreach loop is beyond me. — Ed Swangren
– Ed Swangren, Commented Jan 20, 2010 at 0:03
I think the proposed solutions are equally clear to a foreach loop. — recursive
– recursive, Commented Jan 20, 2010 at 17:39
I believe that foreach is not the same as above because linq statement will be converted to sql that doesn't return each service (because it contains where clause). Using foreach, you return everything (i.e. select *) then you iterate over each record. That is ofc, very different. In this particular example its not important becuase AllServices already selects all records but if it returned query it would not be the same. — majkinetor
– majkinetor, Commented Mar 4, 2010 at 14:05
@majkinetor: There is no database involved in this code at all. Why are you talking about sql? — recursive
– recursive, Commented Oct 7, 2014 at 21:56

recursive · Accepted Answer · 2010-01-19 23:22:14Z

16

Use the Any linq extension method:

public bool IsServiceRunning(string serviceName)
{
    string[] services =  client.AllServices();
    return services.Any(s => 
        s.Equals(serviceName, StringComparison.InvariantCultureIgnoreCase));
}

This way as soon as a match is found, execution will stop.

answered Jan 19, 2010 at 23:22

recursive

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Comments

Ahmad Mageed · Accepted Answer · 2010-01-19 23:20:46Z

8

Try:

return services.Any(s =>
            s.Equals(serviceName, StringComparison.InvariantCultureIgnoreCase));

answered Jan 19, 2010 at 23:20

Ahmad Mageed

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1 Comment

Ahmad Mageed Over a year ago

@recursive: yep, I saw that horizontal scrollbar and the rest is history :)

LukeH · Accepted Answer · 2010-01-19 23:53:25Z

4

A non-LINQ alternative:

public bool IsServiceRunning(string serviceName)
{
    string[] services =  client.AllServices();
    return Array.Exists(services,
        s => s.Equals(serviceName, StringComparison.InvariantCultureIgnoreCase));
}

answered Jan 19, 2010 at 23:53

LukeH

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Comments

LukeH · Accepted Answer · 2010-01-21 09:24:36Z

2

How about this?

public bool IsServiceRunning(string serviceName)
{
    string[] services =  client.AllServices();
    foreach( string service in services )
    {
        if( service.Equals( serviceName, StringComparison.OrdinalIgnoreCase ) )
        {
            return true;
        }
    }

    return false;
}

Really, it is that simple, now get back to work solving real problems. ;)

edited Jan 21, 2010 at 9:24

LukeH

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answered Jan 20, 2010 at 0:20

Ed Swangren

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1 Comment

noctonura Over a year ago

Ya ya good point but I am interested in learning the language features as well :).

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