Java 波特斯特默代码
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时间：2020-08-16 07:14:31 来源:igfitidea点击:
Porter Stemmer code
提问by user872009
I am kinda new to java. I am taking a course in NLP. I wanna know how I can run an input file on the porter stemmer java code.
我对java有点陌生。我正在学习 NLP 课程。我想知道如何在 porter stemmer java 代码上运行输入文件。
回答by agarwav
The class below is named PorterAlgo and has various functions for stemming.
下面的类被命名为 PorterAlgo 并且具有用于词干提取的各种函数。
package com.mycompany.algo;
class NewString {
public String str;
NewString() {
str = "";
}
}
public class PorterAlgo {
String Clean( String str ) {
int last = str.length();
new Character( str.charAt(0) );
String temp = "";
for ( int i=0; i < last; i++ ) {
if ( Character.isLetterOrDigit( str.charAt(i) ) )
temp += str.charAt(i);
}
return temp;
} //clean
boolean hasSuffix( String word, String suffix, NewString stem ) {
String tmp = "";
if ( word.length() <= suffix.length() )
return false;
if (suffix.length() > 1)
if ( word.charAt( word.length()-2 ) != suffix.charAt( suffix.length()-2 ) )
return false;
stem.str = "";
for ( int i=0; i<word.length()-suffix.length(); i++ )
stem.str += word.charAt( i );
tmp = stem.str;
for ( int i=0; i<suffix.length(); i++ )
tmp += suffix.charAt( i );
if ( tmp.compareTo( word ) == 0 )
return true;
else
return false;
}
boolean vowel( char ch, char prev ) {
switch ( ch ) {
case 'a': case 'e': case 'i': case 'o': case 'u':
return true;
case 'y': {
switch ( prev ) {
case 'a': case 'e': case 'i': case 'o': case 'u':
return false;
default:
return true;
}
}
default :
return false;
}
}
int measure( String stem ) {
int i=0, count = 0;
int length = stem.length();
while ( i < length ) {
for ( ; i < length ; i++ ) {
if ( i > 0 ) {
if ( vowel(stem.charAt(i),stem.charAt(i-1)) )
break;
}
else {
if ( vowel(stem.charAt(i),'a') )
break;
}
}
for ( i++ ; i < length ; i++ ) {
if ( i > 0 ) {
if ( !vowel(stem.charAt(i),stem.charAt(i-1)) )
break;
}
else {
if ( !vowel(stem.charAt(i),'?') )
break;
}
}
if ( i < length ) {
count++;
i++;
}
} //while
return(count);
}
boolean containsVowel( String word ) {
for (int i=0 ; i < word.length(); i++ )
if ( i > 0 ) {
if ( vowel(word.charAt(i),word.charAt(i-1)) )
return true;
}
else {
if ( vowel(word.charAt(0),'a') )
return true;
}
return false;
}
boolean cvc( String str ) {
int length=str.length();
if ( length < 3 )
return false;
if ( (!vowel(str.charAt(length-1),str.charAt(length-2)) )
&& (str.charAt(length-1) != 'w') && (str.charAt(length-1) != 'x') && (str.charAt(length-1) != 'y')
&& (vowel(str.charAt(length-2),str.charAt(length-3))) ) {
if (length == 3) {
if (!vowel(str.charAt(0),'?'))
return true;
else
return false;
}
else {
if (!vowel(str.charAt(length-3),str.charAt(length-4)) )
return true;
else
return false;
}
}
return false;
}
String step1( String str ) {
NewString stem = new NewString();
if ( str.charAt( str.length()-1 ) == 's' ) {
if ( (hasSuffix( str, "sses", stem )) || (hasSuffix( str, "ies", stem)) ){
String tmp = "";
for (int i=0; i<str.length()-2; i++)
tmp += str.charAt(i);
str = tmp;
}
else {
if ( ( str.length() == 1 ) && ( str.charAt(str.length()-1) == 's' ) ) {
str = "";
return str;
}
if ( str.charAt( str.length()-2 ) != 's' ) {
String tmp = "";
for (int i=0; i<str.length()-1; i++)
tmp += str.charAt(i);
str = tmp;
}
}
}
if ( hasSuffix( str,"eed",stem ) ) {
if ( measure( stem.str ) > 0 ) {
String tmp = "";
for (int i=0; i<str.length()-1; i++)
tmp += str.charAt( i );
str = tmp;
}
}
else {
if ( (hasSuffix( str,"ed",stem )) || (hasSuffix( str,"ing",stem )) ) {
if (containsVowel( stem.str )) {
String tmp = "";
for ( int i = 0; i < stem.str.length(); i++)
tmp += str.charAt( i );
str = tmp;
if ( str.length() == 1 )
return str;
if ( ( hasSuffix( str,"at",stem) ) || ( hasSuffix( str,"bl",stem ) ) || ( hasSuffix( str,"iz",stem) ) ) {
str += "e";
}
else {
int length = str.length();
if ( (str.charAt(length-1) == str.charAt(length-2))
&& (str.charAt(length-1) != 'l') && (str.charAt(length-1) != 's') && (str.charAt(length-1) != 'z') ) {
tmp = "";
for (int i=0; i<str.length()-1; i++)
tmp += str.charAt(i);
str = tmp;
}
else
if ( measure( str ) == 1 ) {
if ( cvc(str) )
str += "e";
}
}
}
}
}
if ( hasSuffix(str,"y",stem) )
if ( containsVowel( stem.str ) ) {
String tmp = "";
for (int i=0; i<str.length()-1; i++ )
tmp += str.charAt(i);
str = tmp + "i";
}
return str;
}
String step2( String str ) {
String[][] suffixes = { { "ational", "ate" },
{ "tional", "tion" },
{ "enci", "ence" },
{ "anci", "ance" },
{ "izer", "ize" },
{ "iser", "ize" },
{ "abli", "able" },
{ "alli", "al" },
{ "entli", "ent" },
{ "eli", "e" },
{ "ousli", "ous" },
{ "ization", "ize" },
{ "isation", "ize" },
{ "ation", "ate" },
{ "ator", "ate" },
{ "alism", "al" },
{ "iveness", "ive" },
{ "fulness", "ful" },
{ "ousness", "ous" },
{ "aliti", "al" },
{ "iviti", "ive" },
{ "biliti", "ble" }};
NewString stem = new NewString();
for ( int index = 0 ; index < suffixes.length; index++ ) {
if ( hasSuffix ( str, suffixes[index][0], stem ) ) {
if ( measure ( stem.str ) > 0 ) {
str = stem.str + suffixes[index][1];
return str;
}
}
}
return str;
}
String step3( String str ) {
String[][] suffixes = { { "icate", "ic" },
{ "ative", "" },
{ "alize", "al" },
{ "alise", "al" },
{ "iciti", "ic" },
{ "ical", "ic" },
{ "ful", "" },
{ "ness", "" }};
NewString stem = new NewString();
for ( int index = 0 ; index<suffixes.length; index++ ) {
if ( hasSuffix ( str, suffixes[index][0], stem ))
if ( measure ( stem.str ) > 0 ) {
str = stem.str + suffixes[index][1];
return str;
}
}
return str;
}
String step4( String str ) {
String[] suffixes = { "al", "ance", "ence", "er", "ic", "able", "ible", "ant", "ement", "ment", "ent", "sion", "tion",
"ou", "ism", "ate", "iti", "ous", "ive", "ize", "ise"};
NewString stem = new NewString();
for ( int index = 0 ; index<suffixes.length; index++ ) {
if ( hasSuffix ( str, suffixes[index], stem ) ) {
if ( measure ( stem.str ) > 1 ) {
str = stem.str;
return str;
}
}
}
return str;
}
String step5( String str ) {
if ( str.charAt(str.length()-1) == 'e' ) {
if ( measure(str) > 1 ) {/* measure(str)==measure(stem) if ends in vowel */
String tmp = "";
for ( int i=0; i<str.length()-1; i++ )
tmp += str.charAt( i );
str = tmp;
}
else
if ( measure(str) == 1 ) {
String stem = "";
for ( int i=0; i<str.length()-1; i++ )
stem += str.charAt( i );
if ( !cvc(stem) )
str = stem;
}
}
if ( str.length() == 1 )
return str;
if ( (str.charAt(str.length()-1) == 'l') && (str.charAt(str.length()-2) == 'l') && (measure(str) > 1) )
if ( measure(str) > 1 ) {/* measure(str)==measure(stem) if ends in vowel */
String tmp = "";
for ( int i=0; i<str.length()-1; i++ )
tmp += str.charAt( i );
str = tmp;
}
return str;
}
String stripPrefixes ( String str) {
String[] prefixes = { "kilo", "micro", "milli", "intra", "ultra", "mega", "nano", "pico", "pseudo"};
int last = prefixes.length;
for ( int i=0 ; i<last; i++ ) {
if ( str.startsWith( prefixes[i] ) ) {
String temp = "";
for ( int j=0 ; j< str.length()-prefixes[i].length(); j++ )
temp += str.charAt( j+prefixes[i].length() );
return temp;
}
}
return str;
}
private String stripSuffixes( String str ) {
str = step1( str );
if ( str.length() >= 1 )
str = step2( str );
if ( str.length() >= 1 )
str = step3( str );
if ( str.length() >= 1 )
str = step4( str );
if ( str.length() >= 1 )
str = step5( str );
return str;
}
public String stripAffixes( String str ) {
str = str.toLowerCase();
str = Clean(str);
if (( str != "" ) && (str.length() > 2)) {
str = stripPrefixes(str);
if (str != "" )
str = stripSuffixes(str);
}
return str;
} //stripAffixes
} //class
Given below is a class PorterCheck.java
下面给出的是一个类 PorterCheck.java
package com.mycompany.algo;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.*;
public class PorterCheck {
private static final String DEFAULT_TEST_FILE = "C:/Users/vaibhav/Desktop/rev.txt";
public static void main(String args[]) throws IOException{
PorterAlgo pa = new PorterAlgo();
//checks for vowels in a given string
System.out.println(pa.containsVowel("vaibhav"));
//removes special characters
System.out.println(pa.Clean("vaibhav's book"));
//check for a given suffix
NewString stem = new NewString();
System.out.println(pa.hasSuffix("corresponding","ing",stem));
//stemming the words
ArrayList<String> tok = new ArrayList<String>();
String[] tokens = {"normalize","technical","education"};
for (String x: tokens){
tok.add(x);
}
System.out.println(completeStem(tok));
String fileName = ((args.length > 0) ? args[0] : DEFAULT_TEST_FILE);
FileReader fileReader = new FileReader(new File(fileName));
FileTokenizer fileTokenizer = new FileTokenizer();
List<String> tokens1 = fileTokenizer.tokenize(fileReader);
System.out.println("Tokenizing the input file:");
System.out.print(completeStem(tokens1));
}
//method to completely stem the words in an array list
public static ArrayList<String> completeStem(List<String> tokens1){
PorterAlgo pa = new PorterAlgo();
ArrayList<String> arrstr = new ArrayList<String>();
for (String i : tokens1){
String s1 = pa.step1(i);
String s2 = pa.step2(s1);
String s3= pa.step3(s2);
String s4= pa.step4(s3);
String s5= pa.step5(s4);
arrstr.add(s5);
}
return arrstr;
}
//method to tokenize a file
public static ArrayList<String> fileTokenizer(){
StringTokenizer strtoken = new StringTokenizer("this is a book");
ArrayList<String> filetoken = new ArrayList<String>();
while(strtoken.hasMoreElements()){
filetoken.add(strtoken.nextToken());
}
return filetoken;
}
}
Hope this helps you :D
希望这对你有帮助：D
