Regular Expression to Accept Both Positive and Negative Numbers

What is the regex validation for positive and negative numbers?

Adding -? will do the trick:

^-?[1-9]+([0-9]+)*$

regex pattern to allow positive and negative integers

Assuming you only mention an optional negative sign in front of the number:

xs:pattern value="-?[0-9]{0,10}"

Regex to match positive or negative number or empty string, but not '-' alone

You may make the digits obligatory and enclose the whole number matching part with an optional group:

/^(?:-?\d+)?$/

See the regex demo

Details

• ^ - start of the string
• (?:-?\d+)? - an optional non-capturing group matching 1 or 0 occurrences of:
  
  
  • -? - an optional -
  • \d+ - 1 or more digits
• $ - end of string.

Regex to match positive and negative numbers and text between "" after a character

You may read the file into a string and run the following regex:

var matches = Regex.Matches(filecontents, @"(?m)^\*\w+[\s-[\r\n]]*""?(.*?)""?\r?$")
            .Cast<Match>()
            .Select(x => x.Groups[1].Value)
            .ToList();

See the .NET regex demo.

Details:

• (?m) - RegexOptions.Multiline option on
• ^ - start of a line
• \* - a * char
• \w+ - one or more word chars
• [\s-[\r\n]]* - zero or more whitespaces other than CR and LF
• "? - an optional " char
• (.*?) - Group 1: any zero or more chars other than an LF char, as few as possible
• "? - an optional " char
• \r? - an optional CR
• $ - end of a line/string.

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