At 10:38 AM 6/4/2006, tedd wrote:
for ($i="a"; $i<"z"; $i++)
{
echo($i);
}
-- it stops at "y"
But, if you use --
for ($i="a"; $i<="z"; $i++)
{
echo($i);
}
-- it prints considerably more characters after "z" than what one
would normally expect -- why is that?
Tedd,
The discussion of PHP strings has been interesting; thanks for sparking that.
Of course, your subject line to the contrary, it's not that "z" !=
"z", it's that storing an alphabetic character assumed to be a single
byte in a variable and then incrementing it can result in a two-byte
result. I find it plausible that the statement $a = "a" produces a
two-byte result in the first place, we just don't notice it because
the second byte is turned sideways and is very, very skinny.
I assume you know (but I'll state it anyway for the record) that to
avoid the problems you've encountered by trying to treat apparently
multi-byte PHP string variables like one-byte numerics, you can
simply use numerics themselves:
for ($i = ord("a"); $i <= ord("z"); $i++)
{
echo chr($i);
}
ord() and chr() being the PHP functions to yield the numeric value of
a character and the ASCII character of a numeric value:
http://php.net/ord & http://php.net/chr
To save that hard-working server a few machine cycles, one would
presumably store ord("z") in a variable before the loop began and
test for that each iteration.
Warm regards,
Paul
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