Solved

Intersection of a string

Posted on 2009-07-12
11
228 Views
Last Modified: 2012-05-07
Is there any method to do intersection on String. Say I have a string:
str = car, apple, car, pencil, orange, apple, cup, coffee

I would like to loop through that string and then retrive only the intersected values. so the result would be:
result = car, apple

Can I do this?? Any idea please.
Thanks!!!
0
Comment
Question by:Juuno
  • 4
  • 3
  • 2
  • +1
11 Comments
 
LVL 86

Expert Comment

by:CEHJ
ID: 24834044
That wouldn't be an intersection, that would simply be repeated values
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 24834065
Try something like the following:
        List<String> values = Arrays.asList("car, apple, car, pencil, orange, apple, cup, coffee".split("\\s*,\\s*"));
        Stack<String> s = new Stack<String>();
        Set<String> dups = new HashSet<String>();
        Collections.sort(values);
        s.push("");
        for (String value : values) {
            if (value.equals(s.peek())) {
                dups.add(value);
            }
            else {
                s.push(value);
            }
        }
        System.out.println(dups);

Open in new window

0
 
LVL 92

Expert Comment

by:objects
ID: 24834081
String str = "car,apple,car,pencil,orange,apple,cup,coffee";
Set unique = new HashSet(Arrays.asList(str.split(",")));
0
DevOps Toolchain Recommendations

Read this Gartner Research Note and discover how your IT organization can automate and optimize DevOps processes using a toolchain architecture.

 

Author Comment

by:Juuno
ID: 24834209
@ objects - thanks. but I want to get repeated values, not to reduce duplicate values. I think my title makes u confuse. Thanks anyway.

@ CEHJ, is there anyway I can also get the values of how many times they are repeated ?

Thanks!!
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 24834240
>>@ CEHJ, is there anyway I can also get the values of how many times they are repeated ?

You can keep a Map and increment the count into it, keyed on the value
0
 

Author Comment

by:Juuno
ID: 24834272
ur code is like: if u find an equal string, then put that value into 'dups', right? so, I tried to change like this:

But it printed out like this: {car=1, apple=1}
String test = "car, apple, car, pencil, orange, apple, cup, coffee";
	       List<String> values = Arrays.asList(test.split("\\s*,\\s*"));
	        Stack<String> s = new Stack<String>();
	        Map<String, Integer> dups = new HashMap<String, Integer>();
	        Collections.sort(values);
	        s.push("");
	        int ctn=0;
	        for (String value : values) {
	            if (value.equals(s.peek())) {
	            	if(dups.get(value) == null) {
				        dups.put(value, new Integer(1));
				    } else {
				    	dups.put(value, new Integer(dups.get(value).intValue() + 1));
				    }
				    }
	            else {
	                s.push(value);
	            }
	        }
	        System.out.println(dups);
	}

Open in new window

0
 

Author Comment

by:Juuno
ID: 24834315
I got it:
I should change the value '1' to '2' in this line:
> dups.put(value, new Integer(1)
> dups.put(value, new Integer(2).

Thanks anyway!!

0
 
LVL 86

Expert Comment

by:CEHJ
ID: 24834371
You first of all need to get the count out of the Map if the key exists, and increment it. If the key doesn't exist, you put a count of 1
0
 
LVL 92

Expert Comment

by:objects
ID: 24834405
> @ objects - thanks. but I want to get repeated values, not to reduce duplicate values.

yes saw that. you just need to remove the unique values from the original list.
you will be left with the values that are diped

let me know if you need the code, should only be a couple of lines, you don't need a loop
0
 
LVL 8

Accepted Solution

by:
ozlevanon earned 500 total points
ID: 24860852
You can also achieve that using Collections.frequency method (not that most efficient code, but shorter).
See snippet below.
String str = "car, apple, car, pencil, orange, apple, cup, coffee";
List<String> list = new ArrayList<String>(Arrays.asList(str.split("\\s*,\\s*")));
Set<String> duplicates = new HashSet<String>();
for (String s : list)
{
	if (Collections.frequency(list, s) > 1)
	{
		duplicates.add(s);
	}
}
System.out.println("duplicates = " + duplicates);

Open in new window

0

Featured Post

Are your AD admin tools letting you down?

Managing Active Directory can get complicated.  Often, the native tools for managing AD are just not up to the task.  The largest Active Directory installations in the world have relied on one tool to manage their day-to-day administration tasks: Hyena. Start your trial today.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
firstswap challenge 20 77
Oracle SQL syntax check  without executing 6 54
How to determine if a string is a valid SHA value 7 32
printf performancy 11 40
Java had always been an easily readable and understandable language.  Some relatively recent changes in the language seem to be changing this pretty fast, and anyone that had not seen any Java code for the last 5 years will possibly have issues unde…
Are you developing a Java application and want to create Excel Spreadsheets? You have come to the right place, this article will describe how you can create Excel Spreadsheets from a Java Application. For the purposes of this article, I will be u…
Viewers learn about the “while” loop and how to utilize it correctly in Java. Additionally, viewers begin exploring how to include conditional statements within a while loop and avoid an endless loop. Define While Loop: Basic Example: Explanatio…
Viewers will learn about the regular for loop in Java and how to use it. Definition: Break the for loop down into 3 parts: Syntax when using for loops: Example using a for loop:

770 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question