Regular expression for positive and a negative decimal value in java

Regular expression for negative and positive decimal value so that can be matched with string using pattern and matcher for the correct imple开发者_Python百科mentation can any one will provide me with that

(\+|-)?([0-9]+(\.[0-9]+))

Try This! I've also used this way

"^-?[0-9]{1,12}(?:\.[0-9]{1,4})?$"

Rules:

ex: ^-?[0-9]{1,12}(?:\.[0-9]{1,4})?$
^           # Start of string
[0-9]{1,12} # Match 1-12 digits (i. e. 0-999999999999)
(?:         # Try to match...
\.          # a decimal point
[0-9]{1,4}  # followed by one to three digits (i. e. 0-9999)
)?          # ...optionally
$            # End of string

Try this:

[+-]?\d+\.\d+

+ (BOOL)isStringADecimalNumber:(NSString *)string
{
    NSString *regex = @"([+]|-)?(([0-9]+[.]?[0-9]*)|([0-9]*[.]?[0-9]+))";

    NSPredicate *test = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];

    BOOL stringIsADecimalNumber = [test evaluateWithObject:string];

    return stringIsADecimalNumber;
}

Highlighted below, are the numbers that return TRUE for this regex: