StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>Okay, here's a go at a fuller reimplementation.</p> <pre><code>class MyXRange(object): def __init__(self, a1, a2=None, step=1): if step == 0: raise ValueError("arg 3 must not be 0") if a2 is None: a1, a2 = 0, a1 if (a2 - a1) % step != 0: a2 += step - (a2 - a1) % step if cmp(a1, a2) != cmp(0, step): a2 = a1 self.start, self.stop, self.step = a1, a2, step def __iter__(self): n = self.start while cmp(n, self.stop) == cmp(0, self.step): yield n n += self.step def __repr__(self): return "MyXRange(%d,%d,%d)" % (self.start, self.stop, self.step) # NB: len(self) will convert this to an int, and may fail def __len__(self): return (self.stop - self.start)//(self.step) def __getitem__(self, key): if key < 0: key = self.__len__() + key if key < 0: raise IndexError("list index out of range") return self[key] n = self.start + self.step*key if cmp(n, self.stop) != cmp(0, self.step): raise IndexError("list index out of range") return n def __reversed__(self): return MyXRange(self.stop-self.step, self.start-self.step, -self.step) def __contains__(self, val): if val == self.start: return cmp(0, self.step) == cmp(self.start, self.stop) if cmp(self.start, val) != cmp(0, self.step): return False if cmp(val, self.stop) != cmp(0, self.step): return False return (val - self.start) % self.step == 0 </code></pre> <p>And some testing:</p> <pre><code>def testMyXRange(testsize=10): def normexcept(f,args): try: r = [f(args)] except Exception, e: r = type(e) return r for i in range(-testsize,testsize+1): for j in range(-testsize,testsize+1): print i, j for k in range(-9, 10, 2): r, mr = range(i,j,k), MyXRange(i,j,k) if r != list(mr): print "iter fail: %d, %d, %d" % (i,j,k) if list(reversed(r)) != list(reversed(mr)): print "reversed fail: %d, %d, %d" % (i,j,k) if len(r) != len(mr): print "len fail: %d, %d, %d" % (i,j,k) z = [m for m in range(-testsize*2,testsize*2+1) if (m in r) != (m in mr)] if z != []: print "contains fail: %d, %d, %d, %s" % (i,j,k,(z+["..."])[:10]) z = [m for m in range(-testsize*2, testsize*2+1) if normexcept(r.__getitem__, m) != normexcept(mr.__getitem__, m)] if z != []: print "getitem fail: %d, %d, %d, %s" % (i,j,k,(z+["..."])[:10]) </code></pre>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload