Re^2: Regular Expression Help!

I tried but don't like this:

my $x = ""; 
if($x!~//g)  {

  print "\n There is true data\n";

}
[download]

and this:

my $x = "      "; # just spaces
if($x!~/\s+/g)  {

  print "\n There is true data\n";

}
[download]

Thanks

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Re^3: Regular Expression Help! by kennethk (Abbot) on Jul 02, 2010 at 19:34 UTC
A couple of critiques for your expressions: Since you are only testing once, you do not need the `g` modifier. `//` will match everything. Hence `$x!~//` will always return false. `/\s+/` will match if your string contains at least one space. Hence `$x!~/\s+/` will return false if your string contains at least one space. Changing `$x!~/\s+/` to `$x!~/\S+/` will return true when the string does not contain at least one non-whitespace character, and hence will make your test work. You could use anchors (`^` and `$`) and `` to do what you intend as well with `$x=~/^\s$/`. This translates as requiring that between the start (`^`) and end (`$`) there is exactly 0 or more (`*`) whitespace characters (`\s`). I would suggest reading through perlretut to gain familiarity with this tool.	[reply] [d/l] [select]
Re^3: Regular Expression Help! by ikegami (Patriarch) on Jul 02, 2010 at 19:42 UTC
`if (//g)` makes no sense and it's a bug. It makes even less sense when negated. Get rid of the `g`.	[reply] [d/l] [select]