[Tutor] First realscript + Game of Life

Kent Johnson kent37 at tds.net
Sat Nov 11 20:17:44 CET 2006


Luke Paireepinart wrote:
> Kent Johnson wrote:
>> Luke Paireepinart wrote:
>>> I was trying to make it clear that Python wasn't directly accessing 
>>> the binary from memory with this function Carlos had.
>>> The function just mathematically converted a base-10 number into a 
>>> base-2 number.
>> No. It converts a binary representation of a number into a string 
>> representation of the binary representation of the number. There is no 
>> base-10 number involved.
> Binary is base-2.

yes

> Decimal is base-10.

yes

> Integers in python are base-10.

no. Integers are represented in whatever form the C language 
implementation uses which on most modern computers is binary.

When integers are printed in Python, the string representation of the 
integer is in base-10. The underlying integer is probably not in base 10.

> Python doesn't give him direct access to the bits in memory.

right

> It gives him a base-10 integer (a decimal number)

no.
> he uses a mathematical conversion to go from a decimal integer to a list 
> of binary bits.

no, he uses a mathematical conversion to go from a number represented in 
the internal format used by the C implementation (probably binary) to a 
list of '0' and '1' characters which represent binary bits.

> Do you disagree?

yes.

You have to make a distinction between the bit pattern used to represent 
the integer value, which is binary, and the character pattern used to 
represent the integer.

Kent

> The argument to the function is an integer.
>>> Anyway, I just wanted to make sure that Carlos knew that python 
>>> wasn't directly copying the binary representation from memory into a 
>>> list,
>>> Python was getting the base-10 integer representation out of the binary, 
>> No, there is no base-10 representation anywhere in Carlos' program, at 
>> least not on any computer he is likely to be using to run the program.
>>
>>> and then the function converted this back again into base2 using
>>> binary shifts.  I.E. the sentence 'copy binary numbers from memory' 
>>> made me think Carlos thought the binary was directly copied into a list.
>>> I also clarified that it's not a 'module' it's a function.
>>>
>>> Am I still confused, Kent?
>> Yes. Maybe someone else can explain better than me?
>>
>> Kent
>>
>>
> 
> 
> 




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