Java string skills: How to delete punctuation or last characters

Delete all punctuations of a string

 str = str.replaceAll("[//pP''"]", "");

Unicode encoding is used here. Unicode encoding does not simply define an encoding for a character, but also classifies it.

/pP where lowercase p means property, which means Unicode attribute, and is used for the prefix of Unicode regular expressions.

Capital P means one of the seven character attributes of the Unicode character set: punctuation characters.
The other six are

1. L: letters;
2. M: Marker symbols (usually not appearing alone);
3. Z: delimiter (such as spaces, line breaks, etc.);
4. S: symbols (such as mathematical symbols, currency symbols, etc.);
5. N: numerals (such as Arabic numerals, Roman numerals, etc.);
6. C: Other characters

Regular expression data for Unicode in Java are provided by Unicode organizations. Unicode regular expression standard (all sub-properties can be found)
http://www.unicode.org/reports/tr18/
http://www.unicode.org/Public/UNIDATA/UnicodeData.txt
One line of this text document is a character, the first column is Unicode encoding, the second column is a character name, and the third column is a Unicode attribute.
and some other character information.

Delete the last character of the string
String:

 string s = "1,2,3,4,"

Implement the effect: delete the last ","

method:
1. Use Substring

 s = s.Substring(0,s.Length - 1)

2. Use RTrim

 s = s.ToString().RTrim(',')

3. Use TrimEnd

 s=s.TrimEnd(',')//If you want to delete "4,", you need to write char[] MyChar = {'4',','};s = s.TrimEnd(MyChar);// s = "1,2,3

4. Use lastIndexOf() and deleteCharAt()

 int index = sb.toString().lastIndexOf(',');sb.deleteCharAt(index);