sequence multiplied by -1

[Mel]

Grant Edwards wrote:

> On 2010-09-26, Paul Rubin <no.email at nospam.invalid> wrote:
>> Steven D'Aprano <steve at REMOVE-THIS-cybersource.com.au> writes:
>>> There's nothing obscure or unintuitive about "spam"*3 = "spamspamspam",
> 
>> Why would it not be ["spam","spam","spam"] or even "ssspppaaammm"?
> 
> Because
> 
> 3 * "spam" == "spam" + "spam" + "spam"
> 
> Just like
> 
> 3 * 6 = 6 + 6 + 6
> 
> So now I suppose "+" for string concatenation is a bad thing.

It's awkward for math purists because there's no additive inverse .. hence 
the original poster's idea to simply create one out of the blue. For string 
lengths and list lengths we're stuck with non-negative integers, and no hope 
of general-purpose subtraction.

I wouldn't change it.  As an idiom, ' '*20 is just too handy a way to get a 
20-blank string to give up.

	Mel.