Re: [PHP] Bug #51739 tricky string to float conversion
On 1/09/2011, at 9:53 AM, magic-...@damage.devloop.de wrote: Am Mittwoch, 31. August 2011, 20:48:37 schrieb Shawn McKenzie: On 08/31/2011 09:03 AM, magic-...@damage.devloop.de wrote: Hi, I have opend Bug #51739 in 2010. It was closed as bogus before my last question was answered. It would be fine to know what you think about that bug. In short: var_dump((float)8315e839da08e2a7afe6dd12ec58245d); results in float(INF) This is because 8315 is treated as base and e839da08e2a7afe6dd12ec58245d is treated as an exponent. My hint that e839da08e2a7afe6dd12ec58245d is not a valid exponent was not answered. What do you think about? cheers Daniel The cast to float is truncating the invalid characters and since your string contains a float that is INF (8315e839) before the truncation at the d, then it returns INF. Makes perfect sense. This is what drives me crazy. If I use a string in PHP I don't want PHP to cut this string. Either it uses this string as it is or it gives me an error/warning/false (what ever...). But silently(!!!) using a small piece of a string is not understandable. cheers Daniel The manual clearly states this is how a string is converted into a number: http://php.net/manual/en/language.types.string.php#language.types.string.conversion The value is given by the initial portion of the string. If the string starts with valid numeric data, this will be the value used. Otherwise, the value will be 0 (zero). Valid numeric data is an optional sign, followed by one or more digits (optionally containing a decimal point), followed by an optional exponent. The exponent is an 'e' or 'E' followed by one or more digits. If you don't want the string turned into a number using the documented method, don't use it as one. --- Simon Welsh Admin of http://simon.geek.nz/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Bug #51739 tricky string to float conversion
Simon J Welsh writes: On 1/09/2011, at 9:53 AM, magic-...@damage.devloop.de wrote: Am Mittwoch, 31. August 2011, 20:48:37 schrieb Shawn McKenzie: On 08/31/2011 09:03 AM, magic-...@damage.devloop.de wrote: var_dump((float)8315e839da08e2a7afe6dd12ec58245d); results in float(INF) The cast to float is truncating the invalid characters and since your string contains a float that is INF (8315e839) before the truncation at the d, then it returns INF. Makes perfect sense. If I use a string in PHP I don't want PHP to cut this string. Either it uses this string as it is or it gives me an error/warning/false (what ever...). But silently(!!!) using a small piece of a string is not understandable. The manual clearly states this is how a string is converted into a number: http://php.net/manual/en/language.types.string.php#language.types.string.conversion The value is given by the initial portion of the string. If the string starts with valid numeric data, this will be the value used. Otherwise, the value will be 0 (zero). Valid numeric data is an optional sign, followed by one or more digits (optionally containing a decimal point), followed by an optional exponent. The exponent is an 'e' or 'E' followed by one or more digits. If you don't want the string turned into a number using the documented method, don't use it as one. Ok, then let's discuss the documented behavior ;-) Do you (not the document) really like this behavior? I mean if I am the only one wondering about that behavior it is ok for me. I just want to help PHP. cheers Daniel -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Bug #51739 tricky string to float conversion
Le 01/09/2011 10:43, magic-...@damage.devloop.de a écrit : Simon J Welsh writes: On 1/09/2011, at 9:53 AM, magic-...@damage.devloop.de wrote: Am Mittwoch, 31. August 2011, 20:48:37 schrieb Shawn McKenzie: On 08/31/2011 09:03 AM, magic-...@damage.devloop.de wrote: var_dump((float)8315e839da08e2a7afe6dd12ec58245d); results in float(INF) The cast to float is truncating the invalid characters and since your string contains a float that is INF (8315e839) before the truncation at the d, then it returns INF. Makes perfect sense. If I use a string in PHP I don't want PHP to cut this string. Either it uses this string as it is or it gives me an error/warning/false (what ever...). But silently(!!!) using a small piece of a string is not understandable. The manual clearly states this is how a string is converted into a number: http://php.net/manual/en/language.types.string.php#language.types.string.conversion The value is given by the initial portion of the string. If the string starts with valid numeric data, this will be the value used. Otherwise, the value will be 0 (zero). Valid numeric data is an optional sign, followed by one or more digits (optionally containing a decimal point), followed by an optional exponent. The exponent is an 'e' or 'E' followed by one or more digits. If you don't want the string turned into a number using the documented method, don't use it as one. Ok, then let's discuss the documented behavior ;-) Do you (not the document) really like this behavior? I mean if I am the only one wondering about that behavior it is ok for me. I just want to help PHP. cheers Daniel No professional programmer would like this kind of behavior. But PHP want to be accessible for newbies so we have to deal with that. Hope this will be fixed in the next generation... -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Bug #51739 tricky string to float conversion
On 1/09/2011, at 8:43 PM, magic-...@damage.devloop.de wrote: Simon J Welsh writes: On 1/09/2011, at 9:53 AM, magic-...@damage.devloop.de wrote: Am Mittwoch, 31. August 2011, 20:48:37 schrieb Shawn McKenzie: On 08/31/2011 09:03 AM, magic-...@damage.devloop.de wrote: var_dump((float)8315e839da08e2a7afe6dd12ec58245d); results in float(INF) The cast to float is truncating the invalid characters and since your string contains a float that is INF (8315e839) before the truncation at the d, then it returns INF. Makes perfect sense. If I use a string in PHP I don't want PHP to cut this string. Either it uses this string as it is or it gives me an error/warning/false (what ever...). But silently(!!!) using a small piece of a string is not understandable. The manual clearly states this is how a string is converted into a number: http://php.net/manual/en/language.types.string.php#language.types.string.conversion The value is given by the initial portion of the string. If the string starts with valid numeric data, this will be the value used. Otherwise, the value will be 0 (zero). Valid numeric data is an optional sign, followed by one or more digits (optionally containing a decimal point), followed by an optional exponent. The exponent is an 'e' or 'E' followed by one or more digits. If you don't want the string turned into a number using the documented method, don't use it as one. Ok, then let's discuss the documented behavior ;-) Do you (not the document) really like this behavior? I mean if I am the only one wondering about that behavior it is ok for me. I just want to help PHP. cheers Daniel Yes, I think the way it works is correct. It follows similar conversions when changing from a data type that allows more data to one that allows less. Similar things happen when converting from a floating point to integral value. It also directly correlates to the C functions for doing the same thing (atof, strtod, the like). --- Simon Welsh Admin of http://simon.geek.nz/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] Bug #51739 tricky string to float conversion
Hi, I have opend Bug #51739 in 2010. It was closed as bogus before my last question was answered. It would be fine to know what you think about that bug. In short: var_dump((float)8315e839da08e2a7afe6dd12ec58245d); results in float(INF) This is because 8315 is treated as base and e839da08e2a7afe6dd12ec58245d is treated as an exponent. My hint that e839da08e2a7afe6dd12ec58245d is not a valid exponent was not answered. What do you think about? cheers Daniel -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
