CODEWITHSUNDEEP
javalist
Tum
Tum

Reputation: 3652

Is there any Versatile and Simplest way to check if any 2 lists of String[] or String[][] ... got equaled?

What is the Versatile and Simplest way to check if these 2 lists are equaled:

            List<String[]> list1=new ArrayList<String[]>();
            String[] s1={"1","2"};
            String[] s2={"3","4"};
            list1.add(s1);
            list1.add(s2);

            List<String[]> list2=new ArrayList<String[]>();
            String[] s3={"1","2"};
            String[] s4={"3","4"};
            list2.add(s3);
            list2.add(s4);

Some solutions on internet suggest using Collections.sort

Collections.sort(list1);
Collections.sort(list2);

if(list1.equals(list2)){
    System.out.println("true");
}
else{
    System.out.println("false");
}

but it prints out "false" other suggest using containsAll

if(list1.containsAll(list2)){
     System.out.println("true");
}
else{
     System.out.println("false");
}

but it also prints out "false" seem the 2 above solutions only work with List but not work with List<String[]> or even more complicated List<List<String[]>> So is there any versatile way to check whether any 2 lists are equaled.

Upvotes: 4

Views: 69

Answers (1)

Masudul
Masudul

Reputation: 21961

Use Arrays.deepEquals

boolean isEqual=Arrays.deepEquals(list1.toArray(), list2.toArray());

It is also return true for List<String[][]>, for example

    List<String[][]> list1 = new ArrayList<String[][]>();
    String[][] s1 = {{"1", "2"}, {"1", "2"}};
    String[][] s2 = {{"3", "4"}, {"3", "4"}};
    list1.add(s1);
    list1.add(s2);

    List<String[][]> list2 = new ArrayList<String[][]>();
    String[][] s3 = {{"1", "2"}, {"1", "2"}};
    String[][] s4 = {{"3", "4"}, {"3", "4"}};
    list2.add(s3);
    list2.add(s4);

    boolean isEqual = Arrays.deepEquals(list1.toArray(), list2.toArray());

    System.out.println(isEqual);//will  print true.

According to docs,

  • Returns true if the two specified arrays are deeply equal to one another. Unlike the equals(Object[],Object[]) method, this method is appropriate for use with nested arrays of arbitrary depth.

Upvotes: 5

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