Possible Duplicate:
Compare two Lists for differences
this is myfunction
public List<String[]> comparableListsAreTheSame(List<String> baseList, List<String> resultList, int type)
{
if (type == 1) { }
List<String> baseListCopy = baseList;
List<String> resultListCopy = resultList;
bool sameLength = (baseListCopy.Count == resultList.Count); // are 2 lists have the same length?
List<String> Base = baseListCopy.Except(resultListCopy, StringComparer.InvariantCultureIgnoreCase).ToList(); //Keep unique values
List<String> Result = resultListCopy.Except(baseListCopy, StringComparer.InvariantCultureIgnoreCase).ToList(); //Keep unique values
List<String[]> blocksComparisonSet1 = new List<String[]>(); //we add blocks based on list1; so we could output them to excel
List<String[]> blocksComparisonSet2 = new List<String[]>(); //we add blocks based on list2; so we could output them to excel
List<String[]> blocksComparisonFinal = new List<String[]>(); //we combine list1 and list
//-----------------------------------------------------------------
if (Result.Count > 0 || Base.Count > 0)
{
foreach (String resultLine in Result) //loop over all lines in list 1
{
bool found = false; //if element in base i
String[] resultLineArray = resultLine.Split('*'); //get array from the string
foreach (String baseLine in Base)
{
String[] baseLineArray = baseLine.Split('*');
if (resultLineArray[0].Equals(baseLineArray[0]) && resultLineArray[1].Equals(baseLineArray[1]) && resultLineArray[2].Equals(baseLineArray[2]) && resultLineArray[3].Equals(baseLineArray[3]))
{
String[] NA = new String[2]; //keep results
NA[0] = baseLine; //[0] for base
NA[1] = resultLine; //[1] for result
blocksComparisonSet1.Add(NA);
found = true;
}
}
if (!found)
{
String[] NA = new String[2]; //keep results
NA[0] = "N/A"; //[0] for base
NA[1] = resultLine; //[1] for result
blocksComparisonSet1.Add(NA);
}
}
//-----------------------------------------------------------------
foreach (String baseLine in Base) //loop over all lines in list 2
{
bool found = false; //if element in base i
String[] baseLineArray = baseLine.Split('*'); //get array from the string
foreach (String resultLine in Result)
{
String[] resultLineArray = resultLine.Split('*');
if (resultLineArray[0].Equals(baseLineArray[0]) && resultLineArray[1].Equals(baseLineArray[1]) && resultLineArray[2].Equals(baseLineArray[2]) && resultLineArray[3].Equals(baseLineArray[3]))
{
String[] NA = new String[2]; //keep results
NA[0] = baseLine; //[0] for base
NA[1] = resultLine; //[1] for result
blocksComparisonSet2.Add(NA);
found = true;
}
}
if (!found)
{
String[] NA = new String[2]; //keep results
NA[0] = baseLine; //[0] for base
NA[1] = "N/A"; //[1] for result
blocksComparisonSet2.Add(NA);
}
}
}
//-----------------------------------------------------------------
if (blocksComparisonSet1.Any() || blocksComparisonSet2.Any()) //check if we have any values in out differences lists. if we do, merge them
{
blocksComparisonFinal.AddRange(blocksComparisonSet1); //add records from one list to final list
blocksComparisonFinal.AddRange(blocksComparisonSet2); //add records from second list to final list
HashSet<String[]> s = new HashSet<String[]>(blocksComparisonFinal);
blocksComparisonFinal = s.ToList();
}
blocksComparisonFinal = blocksComparisonSet1.Union(blocksComparisonSet2, new ArrayEqualityComparer<string>()).ToList();
return blocksComparisonFinal;
}
I am new to C# and programming in general and I did multiple loops and matched everything in pretty barabric way. Can I approach it more professional way and do it cleaner and PROPER?
type
parameter for? In general, you could create a class that implements IEqualityComparer<List<string[]>>
and/or a class that implements IEqualityComparer<string[]>
to simplify your code considerably - phoog 2012-04-03 21:18
If you are checking if listA and listB have the same elements you can use this extension method:
public static IEnumerable<TSource> Intersect<TSource>
(
this IEnumerable<TSource> first,
IEnumerable<TSource> second,
Func<TSource, TSource, bool> comparer
)
{
return first.Intersect(second, new LambdaComparer<TSource>(comparer));
}
Which uses the LambdaComparer class.
You can then compare them in this manner:
var compared = listA.Intersect(listB, (a, b) => a == b);
if(compared.Count() == listA.Count())
// they are the same
else
// they are not
I have just a couple of comments.
Your innermost foreach loops can be replaced with List.Contains methods. You're adding a bunch of overhead by splitting it into an array and then looping through that array when you can just compare the strings directly. http://msdn.microsoft.com/en-us/library/bhkz42b3.aspx
Also, your second loop that is looping over all of the lines in list 2 only needs to keep track of the misses, not the hits. The first loop finds the items in (1 & 2) and (1 & not 2) so the second loop is only needed to find the items that are (not 1 & 2) if that makes sense. That will also make it so you won't have to merge the hit/miss lists together at the end.
If you were inclined to sort the lists first, you can do this much more efficiently and cleanly.
I hope this can help.