Finding similar words in multiple string (Intersection)

Question

For example,

String a = "cat dog monkey";
String b = "cat cow monkey";
String c = "cat dog duck";

I wonder whether is there any fast and efficient way to do it in Java, in order to find the intersected words of multiple strings, in this case will be "cat".

I'd say split the strings then do something like http://stackoverflow.com/questions/2851938/efficiently-finding-the-intersection-of-a-variable-number-of-sets-of-strings?rq=1 — Evan Knowles, May 22 '14 at 07:21
You must first define "intersection". Does it include both "position of text" and "Text" ? or is it only the text which you want to check? — TheLostMind, May 22 '14 at 07:24

score 7 · Accepted Answer · answered May 22 '14 at 07:24

I'd split each string to an array, convert it to a Set and use the retainAll method:

String a = "cat dog monkey";
String b = "cat cow monkey";
String c = "cat dog duck";

Set<String> aSet = new HashSet<>(Arrays.asList(a.split(" ")));
Set<String> bSet = new HashSet<>(Arrays.asList(a.split(" ")));
Set<String> cSet = new HashSet<>(Arrays.asList(a.split(" ")));

Set<String> result = new HashSet<>(aSet);
result.retainAll(bSet);
result.retainAll(cSet);

Thank you, retainAll is what I'm looking for. – Xitrum May 22 '14 at 07:33 — Xitrum, May 22 '14 at 07:33

score 1 · Answer 2 · edited May 23 '17 at 10:30

If you know word exists at start of the string you can use method a.startsWith("cat")
If you know word exists at end of the string you can use method a.endsWith("cat")
If it is anywhere in the string a.contains("cat"), but that would be case sensitive.
You can use Regular Expressions also , to find it in any place.

To find intersection , here is a code example already given

[Intersection of two strings in Java

Finding similar words in multiple string (Intersection)

2 Answers2