Hi, scipy.interpolate.spalde accepts float as first argument but does not work with numpy.float64 : With python's float : In [166]: c, type(c) Out[166]: (0.52752752752752752, <type 'float'>) In [167]: x, y = interpolate.spalde(c, tck) => no pb. With numpy.float64 : In [168]: b, type(b) Out[168]: (0.52752752752752752, <type 'numpy.float64'>) In [169]: x, y = interpolate.spalde(b, tck) --------------------------------------------------------------------------- <type 'exceptions.TypeError'> Traceback (most recent call last) /home/loic/Python/test_profil/<ipython console> in <module>() /home/loic/tmp/bluelagoon/lib/python2.5/site-packages/scipy/ interpolate/fitpack.py in spalde(x, tck) 575 parametric = False 576 if parametric: --> 577 return _ntlist(map(lambda c,x=x,t=t,k=k:spalde(x, [t,c,k]),c)) 578 else: 579 try: x=x.tolist() /home/loic/tmp/bluelagoon/lib/python2.5/site-packages/scipy/ interpolate/fitpack.py in <lambda>(c, x, t, k) 575 parametric = False 576 if parametric: --> 577 return _ntlist(map(lambda c,x=x,t=t,k=k:spalde(x, [t,c,k]),c)) 578 else: 579 try: x=x.tolist() /home/loic/tmp/bluelagoon/lib/python2.5/site-packages/scipy/ interpolate/fitpack.py in spalde(x, tck) 581 try: x=list(x) 582 except: x=[x] --> 583 if len(x)>1: 584 return map(lambda x,tck=tck:spalde(x,tck),x) 585 d,ier=_fitpack._spalde(t,c,k,x[0]) <type 'exceptions.TypeError'>: object of type 'float' has no len() It seems to come from the method 'tolist' of numpy.float64, which does not return a list : In [174]: c.tolist() --------------------------------------------------------------------------- <type 'exceptions.AttributeError'> Traceback (most recent call last) /home/loic/Python/test_profil/<ipython console> in <module>() <type 'exceptions.AttributeError'>: 'float' object has no attribute 'tolist' In [175]: b.tolist() Out[175]: 0.52752752752752752 So my question is : why do numpy.float64 have a tolist method, and why does it not return a list ? for information, In [179]: numpy.__version__, scipy.__version__ Out[179]: ('1.0.5.dev4854', '0.7.0.dev4004') -- LB