Regular expression for required format

Question

What will be the best regular expression if I want to intake alphanumerics, '-' and '+' signs. e.g. LA2+4 or td1-23

Answer 1

No magic involved, just specify that your complete string (^...$) must match a sequence of arbitrary length (...*) of alternatively ([...]) upper-case letters (A-Z), lower-case letters (a-z), digits (0-9), the plus sign (+) and the minus sign (-).

The only special case to consider is the fact that the minus sign you want to accept (-) must appear as the last (or first) letter in the option group, since the same character is also used to specify ranges (as in A-Z).

So, the solution is:

    ^[A-Za-z0-9+-]*$

Answer 2

Just use [A-Za-z0-9-+]

Answer 3

Do you want to parse any numerical representation?
Or just a few? In Perl (your language not given)
you could just use:

use Scalar::Util qw( looks_like_number )

my $stuff = get_weird_input();
...

if( looks_like_number($stuff) ) {
  convert( ... )
}
...

Regards

rbo