What's the difference between quantize() and str.format()?

Question

I don't mean what's the technical difference, but rather, what's the faster/more logical or Pythonic, etc. way to do this:

    def __quantized_price(self):
        TWOPLACES = Decimal(10) ** -2
        return self.price.quantize(TWOPLACES)

or

    def __formatted_price(self):
        TWOPLACES = Decimal(10) ** -2
        return '{0:.2f}'.format(self.price)

They seem to be exactly the same so I'm just wondering why they created quantize when

Ummm... The only thing that matters is the technical difference, since they do completely different things. — S.Lott, Jan 06 '10 at 19:56

score 8 · Accepted Answer · answered Jan 06 '10 at 19:11

8

Decimal.quantize returns a new Decimal that has a different value.

''.format() formats a string.

In this particular case printing the result yields the same output. Other than that they are totally different operations returning totally different types.

answered Jan 06 '10 at 19:11

Seth

45,033
10
85
120

Oh, so 5.00 is a different value than 5? – orokusaki Jan 06 '10 at 21:04
Yes, they are very different. Do you remember physics? A value of 5 with three significant digits (+/- 0.005) is not the same as a value of 5 with a single significant digit (+/- 0.5). – Marco Mariani Mar 19 '10 at 14:09

What's the difference between quantize() and str.format()?

1 Answers1