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Count occurrences of a substring: Difference between revisions

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Count occurrences of a substring (view source)

Revision as of 23:23, 19 June 2011

293 bytes removed ,  13 years ago
→‎{{header|Java}}
(→‎{{header|Java}}: added shorter method)
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{{works with|Java|1.5+}}
This method does a match and counts how many times it matches
This method removes the first occurrence of the substring, checks for changes, and continues if something changed. It counts each removal attempt (even if nothing is replaced), so the count starts at -1 to offset the last removal attempt where nothing changed.
<lang java>import java.util.regex.Pattern;
import java.util.regex.Matcher;
 
public class CountSubstring {
public static int countSubstring(String subStr, String str){
int ans = 0;
int ans = -1;//start at -1 since we always count at least 1 replacement
Matcher m = Pattern.compile(Pattern.quote(subStr)).matcher(str);
String newStr = str;
while (m.find())
do{
str = newStr;
newStr = str.replaceFirst(Pattern.quote(subStr), "");//attempt a removal
ans++;//count it
}while(!str.equals(newStr));
return ans;
}
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