### Re^3: Numification of strings

by morgon (Curate)
 on Aug 02, 2010 at 18:01 UTC ( #852509=note: print w/replies, xml ) Need Help??

in reply to Re^2: Numification of strings

in Perl, everything is a string until used in a numeric context

I don't think that is true.

In your example you put quotation-marks around the value, so little surprise that you end up with a string...

Consider this:

```use Devel::Peek;

my \$a = "1";
my \$b = 2;

print Dump(\$a);
print Dump(\$b);
This produces:

```SV = PV(0x98c9700) at 0x98ea3f8
REFCNT = 1
PV = 0x98e6368 "1"\0
CUR = 1
LEN = 4
SV = IV(0x98ea474) at 0x98ea478
REFCNT = 1
IV = 2
As you can see \$a is a string "PV", while \$b is an int "IV", even thought it was never used in an numeric context.

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Re^4: Numification of strings
by ww (Archbishop) on Aug 02, 2010 at 18:27 UTC
"As you can see \$a is a string "PV", while \$b is an int "IV", even thought it was never used in an numeric context."

If you mean what I think you mean -- that \$b is an int BECAUSE it was never used in a numeric content -- I think you're wrong, morgon: \$b IS an IV, because it was instantiated that way... as an integer, without quotes that would have made it a string.

Update: Maybe I have the code tags right... at last.

If you mean what I think you mean ...

:-)

I meant to disprove the theory that a value becomes an int only after being used in a numeric context by showing an example in which a value is only instantiated (and never used in a numeric context), yet still is numeric.

Or less convoluted: I probably meant what you said.

Re^4: Numification of strings
by Marshall (Abbot) on Aug 02, 2010 at 18:11 UTC
I updated my post above:
re: Also of note is that in Perl, a string that looks like a number is still a string until used in a numeric context. Feel free to suggest alternate wording for this sentence.

These leading zero situations can happen when reading DB files of various formats, say from a split() or whatever.

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