[Tutor] Function for converting ints from base10 to base2?

[Brian van den Broek]

Dick Moores said unto the world upon 02/21/2007 08:08 PM:
> At 05:17 PM 2/21/2007, Terry Carroll wrote:

<snip>

>> I like the approach of mapping hex or octal digits posted by Alan and Bob,
>> but, not thinking of that, this would be my straightforward approach:
>>
>> def computeBin(n):
>>      """converts base10 integer n to base2 b as string"""
>>      if n == 0: return '0'
>>      sign = ['','-'][n<0]

<snip>

> 
> Thanks!
> 
> But there's syntax(?) there I've never seen before. "['','-'][n<0]". 
> I see it works:
> 
>  >>> n = -6
>  >>> ['','-'][n<0]
> '-'
>  >>> n = 98
>  >>> ['','-'][n<0]
> ''
> 
> What's this called? I'd like to look it up.


Hi Dick and all,

I don't know that it has a name other than `trickery!' ;-)

But, if you're scratching your head over it:

Python 2.4.4c1 (#2, Oct 11 2006, 21:51:02)
[GCC 4.1.2 20060928 (prerelease) (Ubuntu 4.1.1-13ubuntu5)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
 >>> 1==True
True
 >>> 0==False
True
 >>>

Best,

Brian vdB