How to find a whole word in a String in java

Question

I have a String that I have to parse for different keywords  For example  I have the String    I will come and meet you at the 123woods   And my keywords are    123woods   woods   I should report whenever I have a match and where  Multiple occurrences should also be accounted for  However  for this one  I should get a match only on 123woods  not on woods  This eliminates using String contains   method  Also  I should be able to have a list set of keywords and check at the same time for their occurrence  In this example  if I have  123woods  and  come   I should get two occurrences  Method execution should be somewhat fast on large texts   My idea is to use StringTokenizer but I am unsure if it will perform well  Any suggestions

User · Answer

Looking back at the original question  we need to find some given keywords in a given sentence  count the number of occurrences and know something about where  I don t quite understand what  where  means  is it an index in the sentence    so I ll pass that one    I m still learning java  one step at a time  so I ll see to that one in due time  -   It must be noticed that common sentences  as the one in the original question  can have repeated keywords  therefore the search cannot just ask if a given keyword  exists or not  and count it as 1 if it does exist  There can be more then one of the same  For example      Base sentence  added punctuation  to make it more interesting   String sentence    Say that 123 of us will come by and meet you                       say  at the woods of 123woods        Split it  punctuation taken in consideration  as well   java util List lt String gt  strings                           java util Arrays asList sentence split                  My keywords  java util ArrayList lt String gt  keywords   new java util ArrayList lt  gt     keywords add  123woods    keywords add  come    keywords add  you    keywords add  say      By looking at it  the expected result would be 5 for  Say     come     you     say     123woods   counting  say  twice if we go lowercase  If we don t  then the count should be 4   Say  being excluded and  say  included  Fine  My suggestion is      Set    ready     int counter   0      Go  for String s   strings           Asking if the sentence exists in the keywords  not the other        around  to find repeated keywords in the sentence      Boolean found   keywords contains s toLowerCase         if found                counter             System out println  Found      s               Statistics  if  counter  gt  0        System out println  In sentence      sentence     n                          Count      counter       And the results are   Found  Say Found  come Found  you Found  say Found  123woods In sentence  Say that 123 of us will come by and meet you  say  at the woods of 123woods  Count  5

User · Answer

The example below is based on your comments  It uses a List of keywords  which will be searched in a given String using word boundaries  It uses StringUtils from Apache Commons Lang to build the regular expression and print the matched groups   String text    I will come and meet you at the woods 123woods and all the woods    List lt String gt  tokens   new ArrayList lt String gt     tokens add  123woods    tokens add  woods     String patternString      b     StringUtils join tokens             b   Pattern pattern   Pattern compile patternString   Matcher matcher   pattern matcher text    while  matcher find          System out println matcher group 1        If you are looking for more performance  you could have a look at StringSearch  high-performance pattern matching algorithms in Java

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You can also use regex matching with the  b flag  whole word boundary

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Hope this works for you   String string    I will come and meet you at the 123woods   String keyword    123woods    Boolean found   Arrays asList string split       contains keyword   if found         System out println  Keyword matched the string        http   codigounico blogspot com

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Use regex   word boundaries as others answered    I will come and meet you at the 123woods  matches      b123woods  b        will be true    I will come and meet you at the 123woods  matches      bwoods  b        will be false

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You can use regular expressions  Use Matcher and Pattern methods to get the desired output

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Got a way to match Exact word from String in Android   String full    Hello World  How are you      String one    Hell   String two    Hello   String three    are   String four    ar     boolean is1   isContainExactWord full  one   boolean is2   isContainExactWord full  two   boolean is3   isContainExactWord full  three   boolean is4   isContainExactWord full  four    Log i  Contains Result   is1  -  is2  -  is3  -  is4    Result  false-true-true-false   Function for match word   private boolean isContainExactWord String fullString  String partWord       String pattern      b  partWord    b       Pattern p Pattern compile pattern       Matcher m p matcher fullString       return m find        Done

User · Answer

How about something like Arrays asList String split       contains  xx     See String split   and How can I test if an array contains a certain value

User · Answer

To Match  123woods  instead of  woods    use atomic grouping in regular expresssion  One thing to be noted is that  in a string to match  123woods  alone   it will match the first  123woods  and exits instead of searching the same string further    b   gt 123woods woods  b   it searches 123woods as primary search  once it got matched it exits the search

User · Answer

A much simpler way to do this is to use split     String match    123woods   String text    I will come and meet you at the 123woods    String   sentence   text split    for String word  sentence        if word equals match           return true    return false    This is a simpler  less elegant way to do the same thing without using tokens  etc

User · Answer

The solution seems to be long accepted  but the solution could be improved  so if someone has a similar problem   This is a classical application for multi-pattern-search-algorithms   Java Pattern Search  with Matcher find  is not qualified for doing that   Searching for exactly one keyword is optimized in java  searching for an or-expression uses the regex non deterministic automaton which is backtracking on mismatches  In worse case each character of the text will be processed l times  where l is the sum of the pattern lengths    Single pattern search is better  but not qualified  too  One will have to start the whole search for every keyword pattern  In worse case each character of the text will be processed p times where p is the number of patterns   Multi pattern search will process each character of the text exactly once  Algorithms suitable for such a search would be Aho-Corasick  Wu-Manber  or Set Backwards Oracle Matching  These could be found in libraries like Stringsearchalgorithms or byteseek      example with StringSearchAlgorithms  AhoCorasick stringSearch   new AhoCorasick asList  123woods    woods      CharProvider text   new StringCharProvider  I will come and meet you at the woods 123woods and all the woods   0    StringFinder finder   stringSearch createFinder text    List lt StringMatch gt  all   finder findAll

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Try to match using regular expressions  Match for   b123wood b    b is a word break

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public class FindTextInLine       String match    123woods       String text    I will come and meet you at the 123woods        public void findText              if  text contains match                 System out println  Keyword matched the string

[java] How to find a whole word in a String in java

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