If you use a value as a number, it is a number.

A string that can't be parsed as a number at all will be zero. So, how about something like this:

if ($x==0 && substr($x,0,1) ne '0') {
   # deal with non-number
   }
else {
   # deal with number
   }

[download]
In a real application, you will have a more precise definition of what you want. For example, a spreadsheet formula might be a literal number or a cell reference. For such things, you can write rules to match what your application needs and is documented to accept.

—John

Update:fixed typo in substr, reported by dga. Yea, I typed it without checking perlfunc, and I rarely use substr in real code.

In reply to Re: Checking whether a $var is a number by John M. Dlugosz
in thread Checking whether a $var is a number by George_Sherston

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