CODEWITHSUNDEEP
c#arraysc#-2.0
Zerotoinfinity
Zerotoinfinity

Reputation: 6540

How to compare sequence of two string array

I have two string array

string[] a; 
string[] b;

How can I find that the sequence of element in array a is similar to array b?

As I am using .net2.0 I can't use LINQ.

EDIT

This is what I have tried

foreach (string val2 in a)
                { 
                                       foreach (string val1 in b)
                    {
                        if (val1 == val2)
                        {
                           // Values are same - continue processing
                        }
                        else
                        {
                            // Value not same   -- exit                         }
                    }
                }

Upvotes: 1

Views: 2370

Answers (4)

snir
snir

Reputation: 3127

    /// <summary>
    /// Compare two string array. 
    ///  If both null - return true ; 
    ///  If only one is null - return false ;
    /// </summary>
    bool IsSequenceEqual(string[] a, string[] b)
    {
        if (a == null && b == null) // both null - return true
            return true;
        if (a == null || b == null) // only one is null - return false
            return false;

        if (a.Length != b.Length) // length is different - return false
            return false;

        // check if equal
        for (int i = 0; i < a.Length; i++)
        {
            if (a[i] != b[i])
                return false;
        }
        return true;
    }

Upvotes: 0

Chrono
Chrono

Reputation: 1473

If both lists are sorted you can use one of the other solutions. But if the lists are unsorted you could do the following.

  Dictionary<string, byte> dict = new Dictionary<string, byte>();
  foreach (string s in a)
  {
      dict.Add(s, 0);
  }

  bool same = true;
  foreach (string s in b)
  {
      same &= dict.ContainsKey(s);
      if (!same) 
          break;
  }

You could still do simple test before this like check for equal length and such.

If you could use .NET 4.0 there's the Intersect method for arrays. You can then do a.Intersect(b) and compare the length with the length of a or b. If that is true then the lists are equal because all the elements of both arrays intersect. You can do a similar trick with a.Union(b).

EDIT Use Dictionary instead of ArrayList as suggested by phoog.

Upvotes: 0

cuongle
cuongle

Reputation: 75306

    private bool Compare(string[] a, string[] b)
    {
        if (a.Length != b.Length) return false;

        for (int i = 0; i< a.Length; i++)
            if (a[i] != b[i]) return false;

        return true;
    }

Upvotes: 4

Habib
Habib

Reputation: 223267

I believe you want to see if the elements in both arrays have same value and on same index. You can have a simple method like:

public static bool IsSequenceEqual(string[] a, string[] b)
{
    if (a.Length != b.Length)
        return false;
    for (int i = 0; i < a.Length; i++)
    {
        if (a[i] != b[i])
            return false;
    }
    return true;
}

Upvotes: 3

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