How to remove the last bracket in this case - java

This is my program
package com.util;
public class SplitBy {
public static void main(String args[]) {
String name = "Masala Roasted with peanuts(49)";
String category_id = "";
if (!name.contains(",")) {
if (name.contains("(")) {
String[] parts = name.split("\\(");
category_id = parts[1];
System.out.println(category_id);
}
}
}
}
With this the current output is
49)
Please let me know how to get rmove the closing bracket and produce only
49

You can split the String on both brackets:
String[] parts = name.split("[()]");
[()] is a regular expression matching both the openning and closing brackets. As split() is splitting the String around matches, the closing bracket will not be included in the resulting value.
According to the split() javadoc,
Trailing empty strings are therefore not included in the resulting array.
which means that it won't add an empty element at the end of your array.

You can do something like this:
category_id = category_id.substring(0, category_id.length() - 1);
Which will remove the last character from your String.

You can look for both parentheses and only print the content in between:
category_id = name.substring(name.indexOf("(")+1, name.indexOf(")"));

Check this out
package com.util;
public class SplitBy {
public static void main(String args[]) {
String s = "";
Pattern pattern = Pattern.compile("(?<=)(\\d+)");
String EXAMPLE_TEST = "Masala Roasted with peanuts(49)";
Matcher matcher = pattern.matcher(EXAMPLE_TEST);
while (matcher.find()) {
s = matcher.group(1);
}
System.out.println(s);
}
}

Related

How to Split a String without deleting split character

I would like to split a String into parts, but when the String is split the character shouldn't be deleted.
In my Example, I would like to have the Output:
parts[0]= 4x
parts[1]= -3y
parts[2]= 6z
parts[3]= 3v
This is my Code:
import java.util.Arrays;
public class Polynomaddition {
public static void main(String[] args) {
String fraction = "4x-3y+6z+3v";
String [] parts = fraction.split("(?<=\\[a-z]");
System.out.println(Arrays.toString(parts));
//String result = calculator(fraction);
}
public static String calculator(String s) {
String result = "";
String [] parts = s.split("(?<=[a-z])", -1);
return result;
}
}
Solution 1
In your cases, it seems you want this regex \+|(?=-) :
String[] parts = fraction.split("\\+|(?=-)");
details
split with
\+ plus sign
| or
(?=-) minus without deleting it
Solution 2
Or with your regex but you need to check each result, for example :
String[] parts = Arrays.stream(fraction.split("(?<=[a-z])"))
.map(s -> s.startsWith("+") ? s.substring(1, s.length()) : s)
.toArray(String[]::new);
Outputs
[4x, -3y, 6z, 3v]
I would not use split at all. Instead, use a pattern that matches the actual polynomial term, and use a Matcher, specifically its find and group methods, to extract each matched term:
List<String> parts = new ArrayList<>();
Matcher termMatcher = Pattern.compile("[-+]?\\d+[a-z]").matcher(fraction);
while (termMatcher.find()) {
String part = termMatcher.group();
if (part.startsWith("+")) {
part = part.substring(1);
}
parts.add(part);
}
System.out.println(parts);

Regex for finding http and https url from a string

I have a string which contains multiple url starting from http and https I need to fetch all those url and put into a list.
I have tried below code.
List<String> httpLinksList = new ArrayList<>();
String hyperlinkRegex = "((http:\/\/|https:\/\/)?(([a-zA-Z0-9-]){2,}\.){1,4}([a-zA-Z]){2,6}(\/([a-zA-Z-_\/\.0-9#:?=&;,]*)?)?)";
String synopsis = "This is http://stackoverflow.com/questions and https://test.com/method?param=wasd The code below catches all urls in text and returns urls in list";
Pattern pattern = Pattern.compile(hyperlinkRegex);
Matcher matcher = pattern.matcher(synopsis);
while(matcher.find()){
System.out.println(matcher.find()+" "+matcher.group(1)+" "+matcher.groupCount()+" "+matcher.group(2));
httpLinksList.add(matcher.group());
}
System.out.println(httpLinksList);
I need below result
[http://stackoverflow.com/questions,
https://test.com/method?param=wasd]
But getting below output
[https://test.com/method?param=wasd]
This regex will match all the valid urls, including FTP and other
String urlRegex = "((https?|ftp|gopher|telnet|file):((//)|(\\\\))+[\\w\\d:##%/;$()~_?\\+-=\\\\\\.&]*)";
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class xmlValue {
public static void main(String[] args) {
String text = "This is http://stackoverflow.com/questions and https://test.com/method?param=wasd The code below catches all urls in text and returns urls in list";
System.out.println(extractUrls(text));
}
public static List<String> extractUrls(String text)
{
List<String> containedUrls = new ArrayList<String>();
String urlRegex = "((https?|ftp|gopher|telnet|file):((//)|(\\\\))+[\\w\\d:##%/;$()~_?\\+-=\\\\\\.&]*)";
Pattern pattern = Pattern.compile(urlRegex, Pattern.CASE_INSENSITIVE);
Matcher urlMatcher = pattern.matcher(text);
while (urlMatcher.find())
{
containedUrls.add(text.substring(urlMatcher.start(0),
urlMatcher.end(0)));
}
return containedUrls;
}
}
Output:
[http://stackoverflow.com/questions,
https://test.com/method?param=wasd]
credits #BullyWiiPlaza
So I know this is not exactly what you asked since you are specifically looking for regex, but I thought this would fun to try out with an indexOf variant. I will leave it here as an alternative to the regex someone comes up with:
public static void main(String[] args){
String synopsis = "This is http://stackoverflow.com/questions and https://test.com/method?param=wasd The code below catches all urls in text and returns urls in list";
ArrayList<String> list = splitUrl(synopsis);
for (String s : list) {
System.out.println(s);
}
}
public static ArrayList<String> splitUrl(String s)
{
ArrayList<String> list = new ArrayList<>();
int spaceIndex = 0;
while (true) {
int httpIndex = s.indexOf("http", spaceIndex);
if (httpIndex < 0) {
break;
}
spaceIndex = s.indexOf(" ", httpIndex);
if (spaceIndex < 0) {
list.add(s.substring(httpIndex));
break;
}
else {
list.add(s.substring(httpIndex, spaceIndex));
}
}
return list;
}
All the logic is contained in the splitUrl(String s) method, it takes in a String as a parameter and outputs the ArrayList<String> of all the split urls.
It first searches for the index of any http and then the first space that occurs after the url and substrings the difference. It then uses the space it found as the second parameter in indexOf(String, int) to start searching the String beginning after the http that was already found so it does not repeat the same ones.
Additionally a case had to be made when the http is the final part of the String as there is no space afterward. This is done when the indexOf the space returns negative, I use substring(int) instead of substring(int, int) which will take the current location and substring the rest of the String.
The loop ends when either indexOf returns with a negative, though if the space returns negative it does that final substring operation before the break.
Output:
http://stackoverflow.com/questions
https://test.com/method?param=wasd
Note: As someone mentioned in the comments too, this implementation will work with non-Latin characters such as Hiragana too, which could be an advantage over regex.

How to split a string in JAVA with two different seperators? [duplicate]

I want to split the string "004-034556" into two strings by the delimiter "-":
part1 = "004";
part2 = "034556";
That means the first string will contain the characters before '-', and the second string will contain the characters after '-'.
I also want to check if the string has '-' in it.
Use the appropriately named method String#split().
String string = "004-034556";
String[] parts = string.split("-");
String part1 = parts[0]; // 004
String part2 = parts[1]; // 034556
Note that split's argument is assumed to be a regular expression, so remember to escape special characters if necessary.
there are 12 characters with special meanings: the backslash \, the caret ^, the dollar sign $, the period or dot ., the vertical bar or pipe symbol |, the question mark ?, the asterisk or star *, the plus sign +, the opening parenthesis (, the closing parenthesis ), and the opening square bracket [, the opening curly brace {, These special characters are often called "metacharacters".
For instance, to split on a period/dot . (which means "any character" in regex), use either backslash \ to escape the individual special character like so split("\\."), or use character class [] to represent literal character(s) like so split("[.]"), or use Pattern#quote() to escape the entire string like so split(Pattern.quote(".")).
String[] parts = string.split(Pattern.quote(".")); // Split on the exact string.
To test beforehand if the string contains certain character(s), just use String#contains().
if (string.contains("-")) {
// Split it.
} else {
throw new IllegalArgumentException("String " + string + " does not contain -");
}
Note, this does not take a regular expression. For that, use String#matches() instead.
If you'd like to retain the split character in the resulting parts, then make use of positive lookaround. In case you want to have the split character to end up in left hand side, use positive lookbehind by prefixing ?<= group on the pattern.
String string = "004-034556";
String[] parts = string.split("(?<=-)");
String part1 = parts[0]; // 004-
String part2 = parts[1]; // 034556
In case you want to have the split character to end up in right hand side, use positive lookahead by prefixing ?= group on the pattern.
String string = "004-034556";
String[] parts = string.split("(?=-)");
String part1 = parts[0]; // 004
String part2 = parts[1]; // -034556
If you'd like to limit the number of resulting parts, then you can supply the desired number as 2nd argument of split() method.
String string = "004-034556-42";
String[] parts = string.split("-", 2);
String part1 = parts[0]; // 004
String part2 = parts[1]; // 034556-42
An alternative to processing the string directly would be to use a regular expression with capturing groups. This has the advantage that it makes it straightforward to imply more sophisticated constraints on the input. For example, the following splits the string into two parts, and ensures that both consist only of digits:
import java.util.regex.Pattern;
import java.util.regex.Matcher;
class SplitExample
{
private static Pattern twopart = Pattern.compile("(\\d+)-(\\d+)");
public static void checkString(String s)
{
Matcher m = twopart.matcher(s);
if (m.matches()) {
System.out.println(s + " matches; first part is " + m.group(1) +
", second part is " + m.group(2) + ".");
} else {
System.out.println(s + " does not match.");
}
}
public static void main(String[] args) {
checkString("123-4567");
checkString("foo-bar");
checkString("123-");
checkString("-4567");
checkString("123-4567-890");
}
}
As the pattern is fixed in this instance, it can be compiled in advance and stored as a static member (initialised at class load time in the example). The regular expression is:
(\d+)-(\d+)
The parentheses denote the capturing groups; the string that matched that part of the regexp can be accessed by the Match.group() method, as shown. The \d matches and single decimal digit, and the + means "match one or more of the previous expression). The - has no special meaning, so just matches that character in the input. Note that you need to double-escape the backslashes when writing this as a Java string. Some other examples:
([A-Z]+)-([A-Z]+) // Each part consists of only capital letters
([^-]+)-([^-]+) // Each part consists of characters other than -
([A-Z]{2})-(\d+) // The first part is exactly two capital letters,
// the second consists of digits
Use:
String[] result = yourString.split("-");
if (result.length != 2)
throw new IllegalArgumentException("String not in correct format");
This will split your string into two parts. The first element in the array will be the part containing the stuff before the -, and the second element in the array will contain the part of your string after the -.
If the array length is not 2, then the string was not in the format: string-string.
Check out the split() method in the String class.
This:
String[] out = string.split("-");
should do the thing you want. The string class has many method to operate with a string.
// This leaves the regexes issue out of question
// But we must remember that each character in the Delimiter String is treated
// like a single delimiter
public static String[] SplitUsingTokenizer(String subject, String delimiters) {
StringTokenizer strTkn = new StringTokenizer(subject, delimiters);
ArrayList<String> arrLis = new ArrayList<String>(subject.length());
while(strTkn.hasMoreTokens())
arrLis.add(strTkn.nextToken());
return arrLis.toArray(new String[0]);
}
With Java 8:
List<String> stringList = Pattern.compile("-")
.splitAsStream("004-034556")
.collect(Collectors.toList());
stringList.forEach(s -> System.out.println(s));
Use org.apache.commons.lang.StringUtils' split method which can split strings based on the character or string you want to split.
Method signature:
public static String[] split(String str, char separatorChar);
In your case, you want to split a string when there is a "-".
You can simply do as follows:
String str = "004-034556";
String split[] = StringUtils.split(str,"-");
Output:
004
034556
Assume that if - does not exists in your string, it returns the given string, and you will not get any exception.
The requirements left room for interpretation. I recommend writing a method,
public final static String[] mySplit(final String s)
which encapsulate this function. Of course you can use String.split(..) as mentioned in the other answers for the implementation.
You should write some unit-tests for input strings and the desired results and behaviour.
Good test candidates should include:
- "0022-3333"
- "-"
- "5555-"
- "-333"
- "3344-"
- "--"
- ""
- "553535"
- "333-333-33"
- "222--222"
- "222--"
- "--4555"
With defining the according test results, you can specify the behaviour.
For example, if "-333" should return in [,333] or if it is an error.
Can "333-333-33" be separated in [333,333-33] or [333-333,33] or is it an error? And so on.
To summarize: there are at least five ways to split a string in Java:
String.split():
String[] parts ="10,20".split(",");
Pattern.compile(regexp).splitAsStream(input):
List<String> strings = Pattern.compile("\\|")
.splitAsStream("010|020202")
.collect(Collectors.toList());
StringTokenizer (legacy class):
StringTokenizer strings = new StringTokenizer("Welcome to EXPLAINJAVA.COM!", ".");
while(strings.hasMoreTokens()){
String substring = strings.nextToken();
System.out.println(substring);
}
Google Guava Splitter:
Iterable<String> result = Splitter.on(",").split("1,2,3,4");
Apache Commons StringUtils:
String[] strings = StringUtils.split("1,2,3,4", ",");
So you can choose the best option for you depending on what you need, e.g. return type (array, list, or iterable).
Here is a big overview of these methods and the most common examples (how to split by dot, slash, question mark, etc.)
You can try like this also
String concatenated_String="hi^Hello";
String split_string_array[]=concatenated_String.split("\\^");
Assuming, that
you don't really need regular expressions for your split
you happen to already use apache commons lang in your app
The easiest way is to use StringUtils#split(java.lang.String, char). That's more convenient than the one provided by Java out of the box if you don't need regular expressions. Like its manual says, it works like this:
A null input String returns null.
StringUtils.split(null, *) = null
StringUtils.split("", *) = []
StringUtils.split("a.b.c", '.') = ["a", "b", "c"]
StringUtils.split("a..b.c", '.') = ["a", "b", "c"]
StringUtils.split("a:b:c", '.') = ["a:b:c"]
StringUtils.split("a b c", ' ') = ["a", "b", "c"]
I would recommend using commong-lang, since usually it contains a lot of stuff that's usable. However, if you don't need it for anything else than doing a split, then implementing yourself or escaping the regex is a better option.
For simple use cases String.split() should do the job. If you use guava, there is also a Splitter class which allows chaining of different string operations and supports CharMatcher:
Splitter.on('-')
.trimResults()
.omitEmptyStrings()
.split(string);
The fastest way, which also consumes the least resource could be:
String s = "abc-def";
int p = s.indexOf('-');
if (p >= 0) {
String left = s.substring(0, p);
String right = s.substring(p + 1);
} else {
// s does not contain '-'
}
String Split with multiple characters using Regex
public class StringSplitTest {
public static void main(String args[]) {
String s = " ;String; String; String; String, String; String;;String;String; String; String; ;String;String;String;String";
//String[] strs = s.split("[,\\s\\;]");
String[] strs = s.split("[,\\;]");
System.out.println("Substrings length:"+strs.length);
for (int i=0; i < strs.length; i++) {
System.out.println("Str["+i+"]:"+strs[i]);
}
}
}
Output:
Substrings length:17
Str[0]:
Str[1]:String
Str[2]: String
Str[3]: String
Str[4]: String
Str[5]: String
Str[6]: String
Str[7]:
Str[8]:String
Str[9]:String
Str[10]: String
Str[11]: String
Str[12]:
Str[13]:String
Str[14]:String
Str[15]:String
Str[16]:String
But do not expect the same output across all JDK versions. I have seen one bug which exists in some JDK versions where the first null string has been ignored. This bug is not present in the latest JDK version, but it exists in some versions between JDK 1.7 late versions and 1.8 early versions.
There are only two methods you really need to consider.
Use String.split for a one-character delimiter or you don't care about performance
If performance is not an issue, or if the delimiter is a single character that is not a regular expression special character (i.e., not one of .$|()[{^?*+\) then you can use String.split.
String[] results = input.split(",");
The split method has an optimization to avoid using a regular expression if the delimeter is a single character and not in the above list. Otherwise, it has to compile a regular expression, and this is not ideal.
Use Pattern.split and precompile the pattern if using a complex delimiter and you care about performance.
If performance is an issue, and your delimiter is not one of the above, you should pre-compile a regular expression pattern which you can then reuse.
// Save this somewhere
Pattern pattern = Pattern.compile("[,;:]");
/// ... later
String[] results = pattern.split(input);
This last option still creates a new Matcher object. You can also cache this object and reset it for each input for maximum performance, but that is somewhat more complicated and not thread-safe.
You can split a string by a line break by using the following statement:
String textStr[] = yourString.split("\\r?\\n");
You can split a string by a hyphen/character by using the following statement:
String textStr[] = yourString.split("-");
public class SplitTest {
public static String[] split(String text, String delimiter) {
java.util.List<String> parts = new java.util.ArrayList<String>();
text += delimiter;
for (int i = text.indexOf(delimiter), j=0; i != -1;) {
String temp = text.substring(j,i);
if(temp.trim().length() != 0) {
parts.add(temp);
}
j = i + delimiter.length();
i = text.indexOf(delimiter,j);
}
return parts.toArray(new String[0]);
}
public static void main(String[] args) {
String str = "004-034556";
String delimiter = "-";
String result[] = split(str, delimiter);
for(String s:result)
System.out.println(s);
}
}
Please don't use StringTokenizer class as it is a legacy class that is retained for compatibility reasons, and its use is discouraged in new code. And we can make use of the split method as suggested by others as well.
String[] sampleTokens = "004-034556".split("-");
System.out.println(Arrays.toString(sampleTokens));
And as expected it will print:
[004, 034556]
In this answer I also want to point out one change that has taken place for split method in Java 8. The String#split() method makes use of Pattern.split, and now it will remove empty strings at the start of the result array. Notice this change in documentation for Java 8:
When there is a positive-width match at the beginning of the input
sequence then an empty leading substring is included at the beginning
of the resulting array. A zero-width match at the beginning however
never produces such empty leading substring.
It means for the following example:
String[] sampleTokensAgain = "004".split("");
System.out.println(Arrays.toString(sampleTokensAgain));
we will get three strings: [0, 0, 4] and not four as was the case in Java 7 and before. Also check this similar question.
One way to do this is to run through the String in a for-each loop and use the required split character.
public class StringSplitTest {
public static void main(String[] arg){
String str = "004-034556";
String split[] = str.split("-");
System.out.println("The split parts of the String are");
for(String s:split)
System.out.println(s);
}
}
Output:
The split parts of the String are:
004
034556
import java.io.*;
public class BreakString {
public static void main(String args[]) {
String string = "004-034556-1234-2341";
String[] parts = string.split("-");
for(int i=0;i<parts.length;i++) {
System.out.println(parts[i]);
}
}
}
You can use Split():
import java.io.*;
public class Splitting
{
public static void main(String args[])
{
String Str = new String("004-034556");
String[] SplittoArray = Str.split("-");
String string1 = SplittoArray[0];
String string2 = SplittoArray[1];
}
}
Else, you can use StringTokenizer:
import java.util.*;
public class Splitting
{
public static void main(String[] args)
{
StringTokenizer Str = new StringTokenizer("004-034556");
String string1 = Str.nextToken("-");
String string2 = Str.nextToken("-");
}
}
Here are two ways two achieve it.
WAY 1: As you have to split two numbers by a special character you can use regex
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class TrialClass
{
public static void main(String[] args)
{
Pattern p = Pattern.compile("[0-9]+");
Matcher m = p.matcher("004-034556");
while(m.find())
{
System.out.println(m.group());
}
}
}
WAY 2: Using the string split method
public class TrialClass
{
public static void main(String[] args)
{
String temp = "004-034556";
String [] arrString = temp.split("-");
for(String splitString:arrString)
{
System.out.println(splitString);
}
}
}
You can simply use StringTokenizer to split a string in two or more parts whether there are any type of delimiters:
StringTokenizer st = new StringTokenizer("004-034556", "-");
while(st.hasMoreTokens())
{
System.out.println(st.nextToken());
}
Check out the split() method in the String class on javadoc.
https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#split(java.lang.String)
String data = "004-034556-1212-232-232";
int cnt = 1;
for (String item : data.split("-")) {
System.out.println("string "+cnt+" = "+item);
cnt++;
}
Here many examples for split string but I little code optimized.
String str="004-034556"
String[] sTemp=str.split("-");// '-' is a delimiter
string1=004 // sTemp[0];
string2=034556//sTemp[1];
I just wanted to write an algorithm instead of using Java built-in functions:
public static List<String> split(String str, char c){
List<String> list = new ArrayList<>();
StringBuilder sb = new StringBuilder();
for (int i = 0; i < str.length(); i++){
if(str.charAt(i) != c){
sb.append(str.charAt(i));
}
else{
if(sb.length() > 0){
list.add(sb.toString());
sb = new StringBuilder();
}
}
}
if(sb.length() >0){
list.add(sb.toString());
}
return list;
}
You can use the method split:
public class Demo {
public static void main(String args[]) {
String str = "004-034556";
if ((str.contains("-"))) {
String[] temp = str.split("-");
for (String part:temp) {
System.out.println(part);
}
}
else {
System.out.println(str + " does not contain \"-\".");
}
}
}
To split a string, uses String.split(regex). Review the following examples:
String data = "004-034556";
String[] output = data.split("-");
System.out.println(output[0]);
System.out.println(output[1]);
Output
004
034556
Note:
This split (regex) takes a regex as an argument. Remember to escape the regex special characters, like period/dot.
String s = "TnGeneral|DOMESTIC";
String a[]=s.split("\\|");
System.out.println(a.toString());
System.out.println(a[0]);
System.out.println(a[1]);
Output:
TnGeneral
DOMESTIC
String s="004-034556";
for(int i=0;i<s.length();i++)
{
if(s.charAt(i)=='-')
{
System.out.println(s.substring(0,i));
System.out.println(s.substring(i+1));
}
}
As mentioned by everyone, split() is the best option which may be used in your case. An alternative method can be using substring().

Get string within double quotes along with rest of the string

I have a case where I need to extract the string within double quotes in one var and the rest of the string in another var.
Two possibilities:
String: "Franklin B" Benjamin
Result:
var1 = Franklin B
var2 = Benjamin
String: Benjamin "Franklin B"
Result:
var1 = Benjamin
var2 = Franklin B
Regex/Without regex; I am open to any method.
Give this a try...
Basically you remove any leading delimiter in the string before you perform the split. This way you don't have to worry about a leading empty element.
public static void main(String[] args) {
String testString = "\"Franklin B\" Benjamin";
String testString2 = "Benjamin \"Franklin B\"";
displaySplitResults(mySplit(testString, "\""));
displaySplitResults(mySplit(testString2, "\""));
}
private static String[] mySplit(final String input, final String delim)
{
return input.replaceFirst("^" + delim, "").split(delim);
}
private static void displaySplitResults(String[] splitResults) {
if (splitResults.length == 2) {
String var1 = splitResults[0].trim();
String var2 = splitResults[1].trim();
System.out.println(var1);
System.out.println(var2);
}
}
Results:
Franklin B
Benjamin
Benjamin
Franklin B
A simple non-regex way to do it:
public static String[] split(String input) {
if (input.charAt(0) == '"') {
return input.substring(1).split("\" ");
} else {
return input.substring(0, input.length() - 1).split(" \"");
}
}
First check whether the first character is ". Then remove the quote from either beginning or the end and simply split it.
The following will get you a List with the values you want:
private List<String> getValues(String input) {
List<String> matchList = new ArrayList<>();
Pattern regex = Pattern.compile("[^\\s\"']+|\"[^\"]*\"|'[^']*'");
Matcher regexMatcher = regex.matcher(input);
while (regexMatcher.find()) {
matchList.add(regexMatcher.group());
}
return matchList;
}
Taken from Regex for splitting a string using space when not surrounded by single or double quotes
#Shar1er80 Nice piece of work without regex. Worked great.
I also tried with regex:
//Using regex to get values separated by whitespace but keeping values with double quotes
RegexOptions options = RegexOptions.None;
Regex regex = new Regex( #"((""((?<token>.*?)(?<!\\)"")|(?<token>[\w]+))(\s)*)", options );
string input = #" Here is ""my string"" it has "" six matches"" ";
var result = (from Match m in regex.Matches( input )
where m.Groups[ "token" ].Success
select m.Groups[ "token" ].Value).ToList();
Gave me exact result.

Extract the noun words & original sentence from POS Tag

I want to extract the nouns from the sentence and get back the original sentence from the POS Tag
//Extract the words before _NNP & _NN from below and also how to get back the original sentence from the Pos TAG.
Original Sentence:Hi. How are you? This is Mike·
POSTag: Hi._NNP How_WRB are_VBP you?_JJ This_DT is_VBZ Mike._NN
I tried something like this
String txt = "Hi._NNP How_WRB are_VBP you?_JJ This_DT is_VBZ Mike._NN";
String re1 = "((?:[a-z][a-z0-9_]*))"; // Variable Name 1
String re2 = ".*?"; // Non-greedy match on filler
String re3 = "(_)"; // Any Single Character 1
String re4 = "(NNP)"; // Word 1
Pattern p = Pattern.compile(re1 + re2 + re3 + re4, Pattern.CASE_INSENSITIVE | Pattern.DOTALL);
Matcher m = p.matcher(txt);
if (m.find()) {
String var1 = m.group(1);
System.out.print( var1.toString() );
}
}
output: Hi
But I need a list of all the nouns in the sentence.
To extract the nouns, you can do this:
public static String[] extractNouns(String sentenceWithTags) {
// Split String into array of Strings whenever there is a tag that starts with "._NN"
// followed by zero, one or two more letters (like "_NNP", "_NNPS", or "_NNS")
String[] nouns = sentenceWithTags.split("_NN\\w?\\w?\\b");
// remove all but last word (which is the noun) in every String in the array
for(int index = 0; index < nouns.length; index++) {
nouns[index] = nouns[index].substring(nouns[index].lastIndexOf(" ") + 1)
// Remove all non-word characters from extracted Nouns
.replaceAll("[^\\p{L}\\p{Nd}]", "");
}
return nouns;
}
To extract the original sentence, you can do this:
public static String extractOriginal(String sentenceWithTags) {
return sentenceWithTags.replaceAll("_([A-Z]*)\\b", "");
}
Proof that it works:
public static void main(String[] args) {
String sentence = "Hi._NNP How_WRB are_VBP you?_JJ This_DT is_VBZ Mike._NN";
System.out.println(java.util.Arrays.toString(extractNouns(sentence)));
System.out.println(extractOriginal(sentence));
}
Output:
[Hi, Mike]
Hi. How are you? This is Mike.
Note: for the regex that removed all non-word characters (like punctuation) from the extracted nouns, I used this Stack Overflow question/answer.
Use while (m.find()) instead of if (m.find()) to iterate over all the matches.
Moreover, your regex can be really simplified:
if you don't need to capture the data, just don't put parenthesis (usually)
you're using ((?:...)) which is quite strange: a non-capturing group directly nested within a capturing group has no sense.
I'm not sure the .*? part does what you expect. If you want to match a dot, use [.] instead.
Thus, try ([a-z][a-z0-9_]*)[.]_NNP instead.
Or even using positive lookahead: [a-z][a-z0-9_]*(?=[.]_NNP). Use m.group() to access the captured data.
This one should work
import java.util.ArrayList;
public class Test {
public static final String NOUN_REGEX = "[a-zA-Z]*_NN\\w?\\w?\\b";
public static ArrayList<String> extractNounsByRegex(String sentenceWithTags) {
ArrayList<String> nouns = new ArrayList<String>();
String[] words = sentenceWithTags.split("\\s+");
for (int i = 0; i < words.length; i++) {
if(words[i].matches(NOUN_REGEX)) {
System.out.println(" Matched ");
//remove the suffix _NN* and retain [a-zA-Z]*
nouns.add(words[i].replaceAll("_NN\\w?\\w?\\b", ""));
}
}
return nouns;
}
public static String extractOriginal(String word) {
return word.replaceAll("_NN\\w?\\w?\\b", "");
}
public static void main(String[] args) {
// String sentence = "Hi._NNP How_WRB are_VBP you?_JJ This_DT is_VBZ Mike._NN";
String sentence = "Eiffel_NNP tower_NN is_VBZ in_IN paris_NN Hi_NNP How_WRB are_VBP you_PRP This_DT is_VBZ Mike_NNP Barrack_NNP Obama_NNP is_VBZ a_DT president_NN this_VBZ";
System.out.println(extractNounsByRegex(sentence).toString());
System.out.println(sentence);
}
}

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