The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
Help! I'm having a problem in searching through the *elements* if a 2d array. I have a loop over a numpy array: n,m = G.shape print n,m for i in xrange(n): for j in xrange(m): print type(G), type(G[i,j]), type(float(G[i,j])) g = float(abs(G[i,j])) if g < cut: print i,j,G[i,j] However, I'm getting the error message: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all() despite the fact that I'm not computing a truth value of an array. I'd like to just compare to G[i,j] or abs(G[i,j]), which should be a *single* value, and *not* an array. I even call 'float' here to make sure that I cast this to a normal python float. But I still get this error message. At this point, I suspect that I'm doing something dumb, rather than discovering some unique bug in numpy. Can anyone help me out? -- Rick Muller rpmuller@gmail.com 505-750-7557
On Wed, Oct 27, 2010 at 15:58, Rick Muller <rpmuller@gmail.com> wrote:
Help! I'm having a problem in searching through the *elements* if a 2d array. I have a loop over a numpy array:
n,m = G.shape print n,m for i in xrange(n): for j in xrange(m): print type(G), type(G[i,j]), type(float(G[i,j])) g = float(abs(G[i,j])) if g < cut: print i,j,G[i,j]
However, I'm getting the error message:
The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
despite the fact that I'm not computing a truth value of an array. I'd like to just compare to G[i,j] or abs(G[i,j]), which should be a *single* value, and *not* an array. I even call 'float' here to make sure that I cast this to a normal python float. But I still get this error message.
At this point, I suspect that I'm doing something dumb, rather than discovering some unique bug in numpy. Can anyone help me out?
Can you provide a complete, self-contained example that does not work? What kind of object is cut? -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco
Help! I'm having a problem in searching through the *elements* if a 2d array. I have a loop over a numpy array:
n,m = G.shape print n,m for i in xrange(n): for j in xrange(m): print type(G), type(G[i,j]), type(float(G[i,j])) g = float(abs(G[i,j])) if g < cut: print i,j,G[i,j]
However, I'm getting the error message:
The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
despite the fact that I'm not computing a truth value of an array. I'd like to just compare to G[i,j] or abs(G[i,j]), which should be a *single* value, and *not* an array. I even call 'float' here to make sure that I cast this to a normal python float. But I still get this error message.
Which line is raising the error? My guess is it's the only truth-value testing line: "if g < cut". (I'm not sure what else could error here in that way...) It looks like g is probably a scalar, but your code isn't showing where cut comes from, nor have you printed out it's type... is it an array? Zach
Robert, Zachary, Thanks for the quick help. I tried to write a little self-contained example of the crash, but it wasn't working. (I'm sure you've already figured out how this ends.) When I tracked down why it wasn't working, I found my bug. Turned out that cut, which I assumed was just a small scalar value, was actually a matrix, since I was passing in the wrong number of arguments to the function. Hence the confusing error. Thanks again, and sorry for wasting your time. Rick On Wed, Oct 27, 2010 at 3:04 PM, Zachary Pincus <zachary.pincus@yale.edu>wrote:
Help! I'm having a problem in searching through the *elements* if a 2d array. I have a loop over a numpy array:
n,m = G.shape print n,m for i in xrange(n): for j in xrange(m): print type(G), type(G[i,j]), type(float(G[i,j])) g = float(abs(G[i,j])) if g < cut: print i,j,G[i,j]
However, I'm getting the error message:
The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
despite the fact that I'm not computing a truth value of an array. I'd like to just compare to G[i,j] or abs(G[i,j]), which should be a *single* value, and *not* an array. I even call 'float' here to make sure that I cast this to a normal python float. But I still get this error message.
Which line is raising the error? My guess is it's the only truth-value testing line: "if g < cut". (I'm not sure what else could error here in that way...) It looks like g is probably a scalar, but your code isn't showing where cut comes from, nor have you printed out it's type... is it an array?
Zach _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
-- Rick Muller rpmuller@gmail.com 505-750-7557
participants (3)
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Rick Muller -
Robert Kern -
Zachary Pincus