michaelm702
asked on
regular exp
I have a regular expression: "(John) (.+?) "
And String: "John writes about this, and John Doe writes about that, and John Wayne writes about everything."
So I get the following result:
John writes
John Doe
John Wayne
Now I have a another string from user which specifies what needs to be done with the matched strings so for e.g.
%1-%2-%3
%3.%2
[%2]-[%3]-[%1]
So which means I need to replace the %1, %2, %3 etc.. matches with the actual matched items i.e.:
%1-%2-%3 ==== John writes-John Doe-John Wayne
...
How can I do this in Java? The second string which we need to get the matched result into can be of any type but will have the number %1,%2,%3... which we need to replace with the reg ex matches.
I have below code till now:
String covertTo="%1-%2-%3";
String text =
"John writes about this, and John Doe writes about that," +
" and John Wayne writes about everything."
;
String patternString1 = "(John) (.+?) ";
Pattern pattern = Pattern.compile(patternStr
Matcher matcher = pattern.matcher(text);
while (matcher.find()) {
System.out.print("Start index: " + matcher.start());
System.out.print(" End index: " + matcher.end() + " ");
System.out.println("group:
}
//Need to write code to store the above matches into array and replace as required and output to user
And String: "John writes about this, and John Doe writes about that, and John Wayne writes about everything."
So I get the following result:
John writes
John Doe
John Wayne
Now I have a another string from user which specifies what needs to be done with the matched strings so for e.g.
%1-%2-%3
%3.%2
[%2]-[%3]-[%1]
So which means I need to replace the %1, %2, %3 etc.. matches with the actual matched items i.e.:
%1-%2-%3 ==== John writes-John Doe-John Wayne
...
How can I do this in Java? The second string which we need to get the matched result into can be of any type but will have the number %1,%2,%3... which we need to replace with the reg ex matches.
I have below code till now:
String covertTo="%1-%2-%3";
String text =
"John writes about this, and John Doe writes about that," +
" and John Wayne writes about everything."
;
String patternString1 = "(John) (.+?) ";
Pattern pattern = Pattern.compile(patternStr
Matcher matcher = pattern.matcher(text);
while (matcher.find()) {
System.out.print("Start index: " + matcher.start());
System.out.print(" End index: " + matcher.end() + " ");
System.out.println("group:
}
//Need to write code to store the above matches into array and replace as required and output to user
So I get the following result:Ummm, you shouldn't. You haven't really anchored that dot-star, so even though you made it non-greedy, it's still going to match up to the end of the string. Furthermore, you show only two capture groups, but you show 3 replacement backreferences. Is that the actual pattern?
ASKER
actually on trying to go through tutorial for reg ex I was able to find there is a functionality in matcher that allows me to do that:
String input = "Customer Account Number";
String regexe = "([a-z]+) ([a-z]+) ([a-z]+)"; // pattern to be matched
String replacement = "$3 and $2-$1"; // replacement pattern with back references
// Step 1: Allocate a Pattern object to compile a regexe
pattern = Pattern.compile(regexe, Pattern.CASE_INSENSITIVE);
// Step 2: Allocate a Matcher object from the Pattern, and provide the input
matcher = pattern.matcher(input);
// Step 3: Perform the matching and process the matching result
String output = matcher.replaceAll(replace
System.out.println("all: "+output);
output = matcher.replaceFirst(repla
System.out.println("first:
String input = "Customer Account Number";
String regexe = "([a-z]+) ([a-z]+) ([a-z]+)"; // pattern to be matched
String replacement = "$3 and $2-$1"; // replacement pattern with back references
// Step 1: Allocate a Pattern object to compile a regexe
pattern = Pattern.compile(regexe, Pattern.CASE_INSENSITIVE);
// Step 2: Allocate a Matcher object from the Pattern, and provide the input
matcher = pattern.matcher(input);
// Step 3: Perform the matching and process the matching result
String output = matcher.replaceAll(replace
System.out.println("all: "+output);
output = matcher.replaceFirst(repla
System.out.println("first:
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We get it - no one likes a content blocker. Take one extra minute and find out why we block content.
Use the matcher.group() and matcher.groupCount() to loop the results and put into
an array
http://www.java2s.com/Code/Java/Regular-Expressions/Matcher.htm
Regards,
Tomas Helgi