String functions in java

Question

Can we use "contains" and "equalignorecase" functions of string at same time.

i had a data in which i need to search a string "NBN", if found i need to update a flag. But im seeing there are

"nBN","nBn","NBn","nbN","NbN","Nbn"

also existing in the set of data . so i'm getting multiple combinations and comparisons.

Is there any way to overcome these many comparisons by using both functions at a time ?

looks like you're looking for something like a String.containsIgnoreCase(String) method. Is this correct? — Ron
– Ron, Commented Oct 9, 2013 at 4:58
x.toUpperCase().contains(y.toUpperCase()) (beware of the potential NPEs) — user180100
– user180100, Commented Oct 9, 2013 at 4:59

Suresh Atta · Accepted Answer · 2013-10-09 04:58:14Z

5

You can use Apache StringUtils#containsIgnoreCase()

 StringUtils.containsIgnoreCase("WholeString", "NBn");

answered Oct 9, 2013 at 4:58

Suresh Atta

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1 Comment

Ron Over a year ago

Find the source here commons.apache.org/proper/commons-lang/apidocs/src-html/org/… and here commons.apache.org/proper/commons-lang/javadocs/api-3.0/… if you don't want to include commons just for this.

MadProgrammer · Accepted Answer · 2013-10-09 04:59:28Z

4

Think you might find it easier to use String#toLowerCase instead of String#equalsIgnoreCase

For example...

if ("I want my NBN".toLowerCase().contains("nbn")) {...}

answered Oct 9, 2013 at 4:59

MadProgrammer

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2 Comments

MadProgrammer Over a year ago

That makes a nice change :P

Suresh Atta Over a year ago

@user1835935 Can you please mark it as answer, Since your problem solved ??

Ron · Accepted Answer · 2013-10-09 05:06:07Z

2

While there is no built in functionality for this directly, best practice is to convert both Strings to lower case then use contains()

String matchString = "NPN";
String lowercaseMatchString = matchString.toLowerCase();
String lowercase = stringToTest.toLowerCase();

return lowercaseMatchString.contains(lowercase);

edited Oct 9, 2013 at 5:06

answered Oct 9, 2013 at 5:00

Ron

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4 Comments

user180100 Over a year ago

if(a) { return true; }, please use return a;

Ron Over a year ago

Not necessarily, my code allows for further testing if false. Your's returns immediately. If I had a ? return true : return false, I would use return a

user180100 Over a year ago

You edit make my comment void, for sure, but why did you add the "reverse" contains is kind of a mystery..

Ron Over a year ago

Edited to make more concise and use your input

Ron · Accepted Answer · 2013-10-09 05:09:41Z

From Apache Commons
http://commons.apache.org/proper/commons-lang/apidocs/src-html/org/apache/commons/lang3/StringUtils.html:

1337    public static boolean containsIgnoreCase(final CharSequence str, final CharSequence searchStr) {
1338        if (str == null || searchStr == null) {
1339            return false;
1340        }
1341        final int len = searchStr.length();
1342        final int max = str.length() - len;
1343        for (int i = 0; i <= max; i++) {
1344            if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, len)) {
1345                return true;
1346            }
1347        }
1348        return false;
1349    }

http://commons.apache.org/proper/commons-lang/javadocs/api-3.0/src-html/org/apache/commons/lang3/CharSequenceUtils.html

187        static boolean regionMatches(CharSequence cs, boolean ignoreCase, int thisStart,
188                CharSequence substring, int start, int length)    {
189            if (cs instanceof String && substring instanceof String) {
190                return ((String) cs).regionMatches(ignoreCase, thisStart, ((String) substring), start, length);
191            } else {
192                // TODO: Implement rather than convert to String
193                return cs.toString().regionMatches(ignoreCase, thisStart, substring.toString(), start, length);
194            }
195        }

This really should be included in your previous answer - IMHO
@MadProgrammer, I'd sooner delete it than include with the other answer. I think this method is unnecessarily long and is simply to offer an equivalent alternative to including Commons.

Raghvendra Garg · Accepted Answer · 2013-10-09 07:06:45Z

0

If you just want to check the wether your data contains "NBN" then StringUtils.containsIgnoreCase() is the best option as it serves the exact purpose. But if you also want to count the occurrences or anything else then writing a custom solution will be a better option.

answered Oct 9, 2013 at 7:06

Raghvendra Garg

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