(forwarding the private reply to the group) On 01/07/2013 09:03 PM, Nac Temha wrote: > Thanks. I using version 2.7 .I want to understand how to handling big > number. Just want to know logic. Without going into further details but I > want to learn logic of this issue. How to keep datas in python? Using data > structure? and datas how to handling for calculating? > >
Since I don't understand your questions, I'll make some guesses. If these don't cover it, please reword your questions. I'll assume you do NOT want internal details of how the python interpreter manages it. I'll assume you DO want to know how to write your python program so that as much accuracy as possible is used in the calculations. First comment - as soon as you introduce a floating point (non-integer) value into the expression, you have the potential of losing precision. In general, when doing mixed arithmetic, python will convert the result to float. Lots can be written (and has been written) about floats, Decimals, quantization and rounding. I'm again assuming you're NOT asking about these. In Python 2.7, there are two kinds of integers, int and long. An int is limited to some processor-specific size, usually 32 or 64 bits. A long has no practical limit, though after a few hundred million digits, it gets pretty memory hungry and piggishly slow. A long is NOT related to the C type of the same name. If you have an integer in your source code that's larger than that limit, it'll automatically be promoted to long. If you want to see the type of a particular object, you can use type(myobj). For example, print type(2397493749328734972349873) will print: <type 'long'> If you add, subtract, multiply or ** two int objects, and the result is too big for an int, it'll automatically be promoted to long. If you divide two integers with / the result is floored. Thus the result is an integer. That changes in Python 3, where you can get this result with //. If you call some library function on a long, it may or may not be able to handle it, check the docs. But in your own code, it's pretty easy to keep things clean. If you have more questions, please be specific. -- DaveA -- http://mail.python.org/mailman/listinfo/python-list
