Nestor Florez wrote: > Hi there, > > I am trying to read a file and find the last numeric value in the line read. > example: > 123 45 -23 56 <-3.45 > 145 555 112 -12.0 -2.55 > > all of the values are separated by a space and I am looking for the last > value. > I tried
If you know that the values are separated by a space you are better of using split. (type perldoc -f split at the command line) > > > $_ = s/[-][0-9].+$/$1/; > $number = $1; > > > The problem is that, not aleways I am getting the last value starting at the > negative value. > Somtime I get the second to last value. The reason for this is that your regex matches a '-' sign (you don't need to put this inside a '[ ]'). After this it matches a number [0-9] once. A '.' is a regex metacharacter that matches any character (except a newline). A .+$ matches all the characters for there on till the line end. Taking your first string as an example $_ = "123 45 -23 56 <-3.45"; This is how the matching happens. The '-' matches the minus sign of -23. [0-9] matches the 2 of -23. The .+$ matches everything after that, i.e. from the '3' of -23 till the end of the line. The matched string is "-23 56 <-3.45". For the second string the matched string is "-12.0 -2.55". As I have mentioned before if you know the numbers are separated by a space using split would be a better option. hth, Sudarsan
