英文:
Regex ignore tokens that do not start with letter
问题
如何编写一个正则表达式，可以忽略不以字母开头的任何标记？它应该在Java中使用。
示例：it 's super cool --> 正则表达式应匹配：[it, super, cool]，并忽略['s]。
英文:
how can I write a regex that ignores any token that does not start with a letter? it should be used in java.
example: it 's super cool --> regex should match: [it, super, cool] and ignore ['s].
答案1
得分: 0
你可以使用(?<!\\p{Punct})(\\p{L}+)，这表示不在标点符号前面的字母。注意，(?<!用于指定负向后查看。详细了解请查阅Pattern的文档。
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
public static void main(String[] args) {
String str = "it's super cool";
Pattern pattern = Pattern.compile("(?<!\\p{Punct})(\\p{L}+)");
Matcher matcher = pattern.matcher(str);
while (matcher.find()) {
System.out.println(matcher.group());
}
}
}
输出结果:
it
super
cool
英文:
You can use (?<!\\p{Punct})(\\p{L}+) which means letters not preceded by a punctuation mark. Note that (?<! is used to specify a negative look behind. Check the documentation of Pattern to learn more about it.
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
public static void main(String[] args) {
String str = "it 's super cool";
Pattern pattern = Pattern.compile("(?<!\\p{Punct})(\\p{L}+)");
Matcher matcher = pattern.matcher(str);
while (matcher.find()) {
System.out.println(matcher.group());
}
}
}
Output:
it
super
cool
答案2
得分: 0
替代正则表达式:
"(?:^|\\s)([A-Za-z]+)"
上下文中的正则表达式:
public static void main(String[] args) {
String input = "it's super cool";
Matcher matcher = Pattern.compile("(?:^|\\s)([A-Za-z]+)").matcher(input);
while (matcher.find()) {
String result = matcher.group(1);
System.out.println(result);
}
}
输出:
it
super
cool
注意: 若要匹配任何语言（如印地语、德语、中文、英语等）中的字母字符，请使用以下正则表达式：
"(?:^|\\s)(\\p{L}+)"
有关Pattern类以及Unicode脚本、块、类别和二进制属性的类的更多信息，请参见此处。
英文:
Alternative regex:
"(?:^|\\s)([A-Za-z]+)"
Regex in context:
public static void main(String[] args) {
String input = "it 's super cool";
Matcher matcher = Pattern.compile("(?:^|\\s)([A-Za-z]+)").matcher(input);
while (matcher.find()) {
String result = matcher.group(1);
System.out.println(result);
}
}
Output:
it
super
cool
Note: To match alphabetic characters, letters, in any language (e.g. Hindi, German, Chinese, English etc.), use the following regex instead:
"(?:^|\\s)(\\p{L}+)"
More about the class, Pattern and the classes for Unicode scripts, blocks, categories and binary properties, can be found here.
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