Array Sequence Validation

David Smith

Below I have an array, Im trying to come up with a unique linq or unique slick way to do this to validate My State Field or State Array. The correct sequence is On/Off , On/Off.

The last entry must always be an Off.

The sequence can not be an Off/Off, Off/On, On/On. If my array has an invalid entry I want to do something. Can someone assist me.

Correct Array Below:

TStamp	State
1:05	On
1:10	Off
1:15	On
1:20	Off
1:25	On
1:30	Off

Wrong Array Below:

TStamp	State
1:05	On
1:10	On
1:15	On
1:20	Off
1:25	On
1:30	Off

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes13y ago
Accepted answer
The following uses regular expressions rather than LINQ though it's the not the usual way one would validate such a sequence:

using System;
using System.Text.RegularExpressions;

class Test
{
static void Main()
{
string[] state1 = {"On", "Off", "On", "Off", "On", "Off"};
string[] state2 = {"On", "On", "On", "Off", "On", "Off"};
Console.WriteLine(Validate(state1)); // True
Console.WriteLine(Validate(state2)); // False
Console.ReadKey();
}

static bool Validate(string[] state)
{
string text = String.Join("", state);
string regExp = "^(OnOff)+$";
return Regex.IsMatch(text, regExp);
}
}

It can, of course, be easily turned into a one-liner if that's what's needed:

bool isValid = Regex.IsMatch (String.Join("", state), "^(OnOff)+$");
Vulpes13y ago
Try this revised version:

using System;
using System.Linq;
using System.Text.RegularExpressions;

class Test
{
static void Main()
{
string[] ArrayElement = new string[6];
ArrayElement[0]= "1:05:00 PM 06/25/2013 On";
ArrayElement[1]= "1:10:00 PM 06/25/2013 Off";
ArrayElement[2]= "1:15:00 PM 06/25/2013 On";
ArrayElement[3]= "1:20:00 PM 06/25/2013 Off";
ArrayElement[4]= "1:25:00 PM 06/25/2013 On";
ArrayElement[5]= "1:30:00 PM 06/25/2013 Off";

Console.WriteLine(Validate(ArrayElement)); // True

ArrayElement[2]= "1:15:00 PM 05/25/2013 On";
Console.WriteLine(Validate(ArrayElement)); // False
Console.ReadKey();
}

static bool Validate(string[] state)
{
string f = "h:mm:ss tt MM/dd/yyyy";

// extract time stamps and make sure they're in sequence
DateTime[] stamps = state
.Select(s => DateTime.ParseExact(s.Substring(0, s.LastIndexOf(" ")), f, null)).ToArray();
for(int i = 1; i < stamps.Length; i++)
{
if(stamps[i] < stamps[i-1]) return false;
}

// extract On/Off's and validate them
state = state.Select(s => s.Substring(s.IndexOf("O"))).ToArray();
string text = String.Join("", state);
string regExp = "^(OnOff)+$";
return Regex.IsMatch(text, regExp);
}
}
David Smith13y ago
Add a few more things to the logic.

Vuples, I left something out. The State Array will also contain a tStamp and State concatenated together. The format will like this below.

ArrayElement[0]= "1:05:00 PM 06/25/2013 On"
ArrayElement[1]= "1:10:00 PM 06/25/2013 Off"
ArrayElement[2]= "1:15:00 PM 06/25/2013 On"
ArrayElement[3]= "1:20:00 PM 06/25/2013 Off"
ArrayElement[4]= "1:25:00 PM 06/25/2013 On"
ArrayElement[5]= "1:30:00 PM 06/25/2013 Off"

So how to modify regex and logic to account for the entire string logic base upon the array above

static bool Validate(string[] state)
{
string text = String.Join("", state);
string regExp = "^(OnOff)+$";
return Regex.IsMatch(text, regExp);
}

Lastly,

Since the goal is to really add up the time an object has been off, I need to add in some logic to do something if a cycle or element gets corrupt. A complete cycle is On/Off. At the moment your function is only validating whether is the Array has a complete On/Off Cycle.

Let me give an example of an invalid array. The array is been initialized from an input file.

Invalid Array Example: ArrayElement[2] data can't be calculated because, the timestamp is not in range, if that make sense. So if a case like that were to happen, I want to do something, so I am trying to come up with a linq that will account for a perfect sequence and Perfect timestamp sequence.

ArrayElement[0]= "1:05:00 PM 06/25/2013 On"
ArrayElement[1]= "1:10:00 PM 06/25/2013 Off"
ArrayElement[2]= "1:15:00 PM 05/25/2013 On"
ArrayElement[3]= "1:20:00 PM 06/25/2013 Off"
ArrayElement[4]= "1:25:00 PM 06/25/2013 On"
ArrayElement[5]= "1:30:00 PM 06/25/2013 Off"
Hemant Srivastava13y ago
Is there any condition on starting state.. I mean, starting state must be 'ON' or it could be 'OFF'.