Hi Kebin, > I'm testing php 7.1 in my project, and I got a strange problem. > > $string = '584e82ed00819'; > echo (int)$string; > > The above code will output 9223372036854775807 (It's PHP_INT_MAX) in php > 7.1. > In php 5.5, the result is: 584. > > According to the document: > http://php.net/manual/en/language.types.string.php#language.types.string.conversion > > I guess php 7.1 process the string as 584e82, but 5.5 did not. > Any differences for string conversion between 7.1 and 5.5 ? Yes, PHP 7.1 brings the change of string casting now recognising scientific notation. A brief mention of this is made in the migration guide: " Integer operations and conversions on numerical strings now respect scientific notation. This also includes the (int) cast operation, and the following functions: intval() (where the base is 10), settype(), decbin(), decoct(), and dechex(). " For more reasoning on why this change has been made, you can view the Warn about invalid strings in arithmetic RFC[1], specifically the "Fractional and scientific notation strings with integer operators" subsection. Thanks, Tom [1]: https://wiki.php.net/rfc/invalid_strings_in_arithmetic
