CODEWITHSUNDEEP
javaapache-stringutils
Reddy SK
Reddy SK

Reputation: 1374

How to get real end index of string found in another string

I am trying to get a range of chars found in another string using Java:

String input = "test test2 Test3";
String substring = "test2";

int diffStart = StringUtils.indexOf(input, substring);
int diffEnd = StringUtils.lastIndexOf(input, substring);

I want to get

But I am getting

Based on Apache's Commons lastIndexOf function it should work:

public static int lastIndexOf(CharSequence seq, CharSequence searchSeq)

Finds the last index within a CharSequence, handling null. This method uses String.lastIndexOf(String) if possible.

StringUtils.lastIndexOf("aabaabaa", "ab") = 4

What am I doing wrong?

Upvotes: 4

Views: 8170

Answers (1)

Bruce Lowe
Bruce Lowe

Reputation: 6203

you probably want

diffStart = String.valueOf(StringUtils.indexOf(strInputString02, strOutputDiff));
diffEnd = diffStart + strOutputDiff.length();

lastIndexOf finds the matching string, but the last instance of it.

E.g. ab1 ab2 ab3 ab4

lastindexof("ab") finds the 4th ab

indexof("ab") finds the 1st ab (position 0)

However, they always return the location of the first character.

If there is only one instance of a substring lastindexof and indexof will give the same index.

(To enhance your example more, you may also want to do some -1 checks in case the substring is not there at all)

Upvotes: 4

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