I'm sure this has probably been covered here in the past, but I've been unable to find a good way to search for it, so I'll just ask.
if( '20110204024217300000' === '20110204024217300264' ) echo 'BAD'; else echo 'GOOD'; results in "GOOD" being echoed. However, if( '20110204024217300000' == '20110204024217300264' ) echo 'BAD'; else echo 'GOOD'; results in "BAD" being echoed. We guessed that probably the strings were both being converted to ints for the comparison (even on a 64-bit platform 20-digit ints are too large), and indeed the documentation says that "If you compare a number with a string or the comparison involves numerical strings, then each string is converted to a number and the comparison performed numerically." My questions are: 1) What is the advantage to converting both strings to ints to compare them? We have code that compares values for updating in a database, and in this case we were explicitly treating the data as strings, but don't always do so. It was very non-obvious to us that comparing a string-type to a string-type results in the type translation when using ==. It seems counter-productive to have to do: if( (string) $a === (string) $b ) ..... in every circumstance where $a and $b are be strings representing very large integers. To be clear, I'm referring specifically to circumstances where the type of the objects on both sides of the == comparison are the same. (Maybe int-strings should be a special case, or perhaps this should apply to any object type?) 2) The documentation (http://www.php.net/manual/en/language.operators.comparison.php) only mentions type juggling for ==, !=, and <>, but not greater-than or less-than comparisons. Does this happen with those as well? (If so, I think it could be helpful to have the documentation show this.) 3) If the expected/desired behavior is really to have both strings converted to ints to do the comparison, it would make sense to me to have a "loss of precision" warning- or something to that effect- when the int exceeds the limits of PHP_INT_SIZE-byte ints. However, other than backward compatibility, I have been unable to think of a reason why two strings containing string-representations of ints should be converted for the comparison-- especially with ==. Thanks for your time everybody, Matt -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
