Bill Baxter: > Python's are a little annoying in that, like D, you can't use > them outside of indexing expressions. Can't even use them in loops. > In NumPy, the numerical library for Python, they've invented some > quirky objects like numpy.r_ which you index to create a range > literal. Like > >>> numpy.r_[0:4:0.5] > array([ 0. , 0.5, 1. , 1.5, 2. , 2.5, 3. , 3.5]) > You could do the same in D, but I don't think anyone in NumPy thinks > of it as a particularly elegant way to make ranges (compared to matlab > where just plain 0:4:0.5 gets you the same thing). Also you'd most > often like to have that 4.0 in there, so you have to tweak the range > to be [0:4.5:0.5] to get that inclusivity, because python doesn't have > inclusive ranges. Not ideal. So they also have
For other people here: >>> class C(object): ... def __getitem__(self, key): return key ... >>> c = C() # creation >>> c[10] 10 >>> c[10:20] slice(10, 20, None) >>> c[10:20:30] slice(10, 20, 30) >>> c[...] Ellipsis So inside __getitem__ (that's like opIndex) the key is turned into a slice object, or even into a built-in Ellipsis object :-) Bye, bearophile
