I have some strings with all kinds of different emojis/images/signs in them.
Not all the strings are in English -- some of them are in other non-Latin languages, for example:
▓ railway??
→ Cats and dogs
I'm on 🔥
Apples ⚛
✅ Vi sign
♛ I'm the king ♛
Corée ♦ du Nord ☁ (French)
gjør at både ◄╗ (Norwegian)
Star me ★
Star ⭐ once more
早上好 ♛ (Chinese)
Καλημέρα ✂ (Greek)
another ✓ sign ✓
добрай раніцы ✪ (Belarus)
◄ शुभ प्रभात ◄ (Hindi)
✪ ✰ ❈ ❧ Let's get together ★. We shall meet at 12/10/ 10:00 AM at Tony's.❉
...and many more of these.
I would like to get rid of all these signs/images and to keep only the letters (and punctuation) in the different languages.
I tried to clean the signs using the EmojiParser library:
String withoutEmojis = EmojiParser.removeAllEmojis(input);
The problem is that EmojiParser is not able to remove the majority of the signs. The ♦ sign is the only one I found till now that it removed.
Other signs such as ✪ ❉ ★ ✰ ❈ ❧ ✂ ❋ ⓡ ✿ ♛ 🔥 are not removed.
Is there a way to remove all these signs from the input strings and keeping only the letters and punctuation in the different languages?
解决方案
Instead of blacklisting some elements, how about creating a whitelist of the characters you do wish to keep? This way you don't need to worry about every new emoji being added.
String characterFilter = "[^\\p{L}\\p{M}\\p{N}\\p{P}\\p{Z}\\p{Cf}\\p{Cs}\\s]";
String emotionless = aString.replaceAll(characterFilter,"");
So:
[\\p{L}\\p{M}\\p{N}\\p{P}\\p{Z}\\p{Cf}\\p{Cs}\\s] is a range representing all numeric (\\p{N}), letter (\\p{L}), mark (\\p{M}), punctuation (\\p{P}), whitespace/separator (\\p{Z}), other formatting (\\p{Cf}) and other characters above U+FFFF in Unicode (\\p{Cs}), and newline (\\s) characters. \\p{L} specifically includes the characters from other alphabets such as Cyrillic, Latin, Kanji, etc.
The ^ in the regex character set negates the match.
Example:
String str = "hello world _# 皆さん、こんにちは！私はジョンと申します。🔥";
System.out.print(str.replaceAll("[^\\p{L}\\p{M}\\p{N}\\p{P}\\p{Z}\\p{Cf}\\p{Cs}\\s]",""));
// Output:
// "hello world _# 皆さん、こんにちは！私はジョンと申します。"
If you need more information, check out the Java documentation for regexes.
