RegEx匹配第二行中的数字

Question

I need a regex to match a number in the second line. Similar input is like this:

^C1.1
xC20 
SS3 
M 4 

Decimal pattern (-?\\d+(\\.\\d+)?) matches all numbers and second number can be get in a loop on the code behind but I need a regular expression to get directly the number in the second line.

Answer 1

/^[^\r\n]*\r?\n\D*?(-?\d+(\.\d+)?)/

This operates by capturing a single line at the beginning of the input:

^         Beginning of the string
[^\r\n]*  Anything that isn't a line terminator
\r?\n     A newline, optionally preceded by a carriage return

Then all the non digit characters, then your numbers.

Since you've now repeatedly changed your needs, try this on for size:

/(?<=\n\D*)-?\d+(\.\d+)?/

Answer 2

我能用这个正则表达式捕获它。

.*\n\D*(\d*).*\n

Answer 3

Check out group 1 of anything that this matches:

^.*?\r\n.*?(\d+)

If that doesn't work, try this:

^.*?\r\n.*?(\d+)

Both are with multiline NOT set...

Answer 4

I would probably use the captured group in /^.*?\\r?\\n.*?(-?\\d+(?:\\.\\d+)?)/ where…

^                  # beginning of string
.*?                # anything...
\r?\n              # followed by a new line
.*?                # anything...
(                  # followed by...
   -?              # an optional negative sign (minus)
   \d+             # a number
   (?:             #   -this part not captured explicitly-
       \.\d+       # a dot and a number
   )?              #   -and is optional-
)

If it is a flavor that supports lookbehind then there are other alternatives.