The regular expression of Leetcode-RegExp

Regular expressions

Some good learning resources:

Microsoft MSDN

Java

Http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html

Others

Http://developer.51cto.com/art/200912/166310.htm

http://luolei.org/2013/09/regula-expression-simple-tutorial/

http://net.tutsplus.com/tutorials/php/regular-expressions-for-dummies-screencast-series/

Http://deerchao.net/tutorials/regex/regex.htm

1. Valid Numbers

Validate if a given string is numeric.

Some Examples:
"0" = True
"0.1" = True
"ABC" = False
"1 A" = False
"2e10" = True

Note:it is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementing one. This problem is simpler with regular expressions, directly matching strings.

public boolean isnumber (String s) {
        if (S.trim (). IsEmpty ())
        	return false;
        String regex = "[-+]?" (\\d+\\.?| \\.\\d+) \\d* (e[-+]?\\d+)? ";
        if (S.trim (). Matches (regex))
        	return true;
        else
        	return false;
    }

2.