CODEWITHSUNDEEP
java
user1063145
user1063145

Reputation: 71

comparision of arraylist

hi am storing the results in array list which are obtained by querying different database in java. i need to compare this array list to get the common rows

      List name = new  ArrayList();
      name.add(Spreadsheets.getString("Name"));

     List namedb = new  ArrayList();
     namedb .add(rs.getString("eName"))

in c++ we use strcmp to compare. but in java how do i compare this arraylist and it should return common rows. or how do i apply binary search algorithm to search these to arraylist?

Upvotes: 0

Views: 135

Answers (3)

Tristian
Tristian

Reputation: 3512

Use the List's retainAll method.

List<String> names = new ArrayList<String>();
List<String> namesDB =  new ArrayList<String>();

// Get some names ??
names.add(Spreadsheets.getString("Name"));

boolean hasCommonNames =  namesDB.retainAll( names );

// The namesDB will only contain the common names.
if( hasCommonNames ) {
    // Do something with the common names
}

Upvotes: 1

Fahim Parkar
Fahim Parkar

Reputation: 31627

ArrayList<Integer> a3 = new ArrayList<Integer>();               
for (String a : a1)
    a3.add(a2.contains(a) ? 1 : 0);

Now check content of a3. If all is 1, two list are same...

Upvotes: 0

Rocky
Rocky

Reputation: 951

You can use a HashMap to store the first set of results , and then iterate through the second list , during iteration check if that value exists in the HashMap , if it exists , push it into another List C , at the end of the iteration , List C will have the common elements

Upvotes: 0

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