It looks like what is needed here are a kind of "mutable float". Is there a simple way of creating such a type? I don't mind changing the value through x.value = 1.23 instead of x = 1.23... :)
On Apr 14, 3:03 pm, eric.le.bi...@spectro.jussieu.fr wrote: > Hello, > > Is there a way to easily build an object that behaves exactly like a > float, but whose value can be changed? The goal is to maintain a list > [x, y,…] of these float-like objects, and to modify their value on the > fly (with something like x.value = 3.14) so that any expression like "x > +y" uses the new value. > > I thought of two solutions, both of which I can't make to work: > > 1) Use a class that inherits from float. This takes care of the > "behave like float" part. But is it possible to change the value of > the float associated with an instance? That is, is it possible to > do: "x = MyFloat(1.23); x.change_value(3.14)" so that x's float value > becomes 3.14? > > 2) The other possibility I thought of was: use a class that defines a > 'value' member (x.value). This takes care of the "value can be > changed" part. But is it possible/easy to make it fully behave like a > float (including when passed to functions like math.sin)? > > Alternatively, I'd be happy with a way of handling numerical > uncertainties in Python calculations (such as in "calculate the value > and uncertainty of a*sin(b) knowing that a=3.0 +/- 0.1 and b=1.00 +/- > 0.01"). > > Any idea would be much appreciated! -- http://mail.python.org/mailman/listinfo/python-list
