I have a list with some Belgian cities with diacritic characters: (Liège, Quiévrain, Franière, etc.) and I would like to transform these special characters to compare with a list containing the same names in upper case, but without the diacritical marks (LIEGE, QUIEVRAIN, FRANIERE)
What i first tried to do was to use the upper case:
LIEGE.contentEqual(Liège.toUpperCase()) but that doesn't fit because the Upper case of Liège is LIÈGE and not LIEGE.
I have some complicated ideas like replacing each character, but that sounds stupid and a long process.
Any ideas on how to do this in a smart way?
Check out this method in Java
private static final String PLAIN_ASCII = "AaEeIiOoUu" // grave
+ "AaEeIiOoUuYy" // acute
+ "AaEeIiOoUuYy" // circumflex
+ "AaOoNn" // tilde
+ "AaEeIiOoUuYy" // umlaut
+ "Aa" // ring
+ "Cc" // cedilla
+ "OoUu" // double acute
;
private static final String UNICODE = "\u00C0\u00E0\u00C8\u00E8\u00CC\u00EC\u00D2\u00F2\u00D9\u00F9"
+ "\u00C1\u00E1\u00C9\u00E9\u00CD\u00ED\u00D3\u00F3\u00DA\u00FA\u00DD\u00FD"
+ "\u00C2\u00E2\u00CA\u00EA\u00CE\u00EE\u00D4\u00F4\u00DB\u00FB\u0176\u0177"
+ "\u00C3\u00E3\u00D5\u00F5\u00D1\u00F1"
+ "\u00C4\u00E4\u00CB\u00EB\u00CF\u00EF\u00D6\u00F6\u00DC\u00FC\u0178\u00FF"
+ "\u00C5\u00E5" + "\u00C7\u00E7" + "\u0150\u0151\u0170\u0171";
/**
* remove accented from a string and replace with ascii equivalent
*/
public static String removeAccents(String s) {
if (s == null)
return null;
StringBuilder sb = new StringBuilder(s.length());
int n = s.length();
int pos = -1;
char c;
boolean found = false;
for (int i = 0; i < n; i++) {
pos = -1;
c = s.charAt(i);
pos = (c <= 126) ? -1 : UNICODE.indexOf(c);
if (pos > -1) {
found = true;
sb.append(PLAIN_ASCII.charAt(pos));
} else {
sb.append(c);
}
}
if (!found) {
return s;
} else {
return sb.toString();
}
}
As of Java 6, you can use java.text.Normalizer:
public String unaccent(String s) {
String normalized = Normalizer.normalize(s, Normalizer.Form.NFD);
return normalized.replaceAll("[^\\p{ASCII}]", "");
}
Note that in Java 5 there is also a sun.text.Normalizer, but its use is strongly discouraged since it's part of Sun's proprietary API and has been removed in Java 6.
This is the simplest solution I've found so far and it works perfectly in our applications.
Normalizer.normalize(string, Normalizer.Form.NFD).replaceAll("\\p{InCombiningDiacriticalMarks}+", "");
But I don't know if the Normalizer is available on the Android platform.
If you still need that for Android API 8 or lower (Android 2.2, Java 1.5) where you don't have Normalizer class, here's my code, I think better to modify than Pentium10 answer:
public class StringAccentRemover {
@SuppressWarnings("serial")
private static final HashMap<Character, Character> accents = new HashMap<Character, Character>(){
{
put('Ą', 'A');
put('Ę', 'E');
put('Ć', 'C');
put('Ł', 'L');
put('Ń', 'N');
put('Ó', 'O');
put('Ś', 'S');
put('Ż', 'Z');
put('Ź', 'Z');
put('ą', 'a');
put('ę', 'e');
put('ć', 'c');
put('ł', 'l');
put('ń', 'n');
put('ó', 'o');
put('ś', 's');
put('ż', 'z');
put('ź', 'z');
}
};
/**
* remove accented from a string and replace with ascii equivalent
*/
public static String removeAccents(String s) {
char[] result = s.toCharArray();
for(int i=0; i<result.length; i++) {
Character replacement = accents.get(result[i]);
if (replacement!=null) result[i] = replacement;
}
return new String(result);
}
}
The Collator class is a good way to do it (see corresponding javadoc). Here is a unit test that shows how to use it :
import static org.junit.Assert.assertEquals;
import java.text.Collator;
import java.util.Locale;
import org.junit.Test;
public class CollatorTest {
@Test public void liege() throws Exception {
Collator compareOperator = Collator.getInstance(Locale.FRENCH);
compareOperator.setStrength(Collator.PRIMARY);
assertEquals(0, compareOperator.compare("Liege", "Liege")); // no accent
assertEquals(0, compareOperator.compare("Liège", "Liege")); // with accent
assertEquals(0, compareOperator.compare("LIEGE", "Liege")); // case insensitive
assertEquals(0, compareOperator.compare("LIEGE", "Liège")); // case insensitive with accent
assertEquals(1, compareOperator.compare("Liege", "Bruxelles"));
assertEquals(-1, compareOperator.compare("Bruxelles", "Liege"));
}
}
EDIT : sorry to see my answer did not meet your needs ; maybe it's beause I've presented it as unit test ? Is this ok for you ? I personnaly find it better because it's short and it uses the SDK (no need for String replacement)
Collator compareOperator = Collator.getInstance(Locale.FRENCH);
compareOperator.setStrength(Collator.PRIMARY);
if (compareOperator.compare("Liège", "Liege") == 0) {
// if we are here, then it's the "same" String
}
hope this helps
I don't know if it is avaible on Android but on the JVM, you should not reimplement it in your project and reuse already existing code: just use org.apache.commons.lang3.StringUtils#stripAccents
For those looking for a clean java solution, use apache commons:
StringUtils.stripAccents("Liège").toUpperCase();
this will return
LIEGE
Since class Normalizer is not supported in Froyo or previous Android versions, I have combined this and this (which I both voted up), and optimized it, obtaining a couple of helper methods. Method unaccentify simply converts diacritic chars to plain chars, while method slugify generates a slug for the input string. Hope it can be useful to someone. Here is the source code:
import java.util.Arrays;
import java.util.Locale;
import java.util.regex.Pattern;
public class SlugFroyo {
private static final Pattern STRANGE = Pattern.compile("[^a-zA-Z0-9-]");
private static final Pattern WHITESPACE = Pattern.compile("[\\s]");
private static final String DIACRITIC_CHARS = "\u00C0\u00E0\u00C8\u00E8\u00CC\u00EC\u00D2\u00F2\u00D9\u00F9"
+ "\u00C1\u00E1\u00C9\u00E9\u00CD\u00ED\u00D3\u00F3\u00DA\u00FA\u00DD\u00FD"
+ "\u00C2\u00E2\u00CA\u00EA\u00CE\u00EE\u00D4\u00F4\u00DB\u00FB\u0176\u0177"
+ "\u00C3\u00E3\u00D5\u00F5\u00D1\u00F1"
+ "\u00C4\u00E4\u00CB\u00EB\u00CF\u00EF\u00D6\u00F6\u00DC\u00FC\u0178\u00FF"
+ "\u00C5\u00E5" + "\u00C7\u00E7" + "\u0150\u0151\u0170\u0171";
private static final String PLAIN_CHARS = "AaEeIiOoUu" // grave
+ "AaEeIiOoUuYy" // acute
+ "AaEeIiOoUuYy" // circumflex
+ "AaOoNn" // tilde
+ "AaEeIiOoUuYy" // umlaut
+ "Aa" // ring
+ "Cc" // cedilla
+ "OoUu"; // double acute
private static char[] lookup = new char[0x180];
static {
Arrays.fill(lookup, (char) 0);
for (int i = 0; i < DIACRITIC_CHARS.length(); i++)
lookup[DIACRITIC_CHARS.charAt(i)] = PLAIN_CHARS.charAt(i);
}
public static String slugify(String s) {
String nowhitespace = WHITESPACE.matcher(s).replaceAll("-");
String unaccented = unaccentify(nowhitespace);
String slug = STRANGE.matcher(unaccented).replaceAll("");
return slug.toLowerCase(Locale.ENGLISH);
}
public static String unaccentify(String s) {
StringBuilder sb = new StringBuilder(s);
for (int i = 0; i < sb.length(); i++) {
char c = sb.charAt(i);
if (c > 126 && c < lookup.length) {
char replacement = lookup[c];
if (replacement > 0)
sb.setCharAt(i, replacement);
}
}
return sb.toString();
}
}
来源：https://stackoverflow.com/questions/3211974/ignoring-diacritic-characters-when-comparing-words-with-special-characters-%c3%a9-%c3%a8