Thanks Chris for informative post. cheers,
Chao 2012/5/22 Chris Barker <[email protected]> > On Tue, May 22, 2012 at 6:33 AM, Chao YUE <[email protected]> wrote: > > > Just in case some one didn't know this. Assign a float number to an > integer > > array element will always return integer. > > right -- numpy arrays are typed -- that's one of the points of them -- > you wouldn't want the entire array up-cast with a single assignment -- > particularly since there are only python literals for a subset of the > numpy types. > > > so I would always do this if I expected a transfer from integer to float? > > In [18]: b=a.astype(float) > > yes -- but that's an odd way of thinking about -- what you want to do > is think about what type you need your array to be before you create > it, then create it the way you need it: > > In [87]: np.arange(5, dtype=np.float) > Out[87]: array([ 0., 1., 2., 3., 4.]) > > or better: > > In [91]: np.linspace(0,5,6) > Out[91]: array([ 0., 1., 2., 3., 4., 5.]) > > note that most (all?) numpy array constructors take a "dtype" argument. > > -Chris > > > > > > > In [19]: b > > Out[19]: array([ 2., 4., 6., 8., 10.]) > > > > In [20]: b[1]=4.5 > > > > In [21]: b > > Out[21]: array([ 2. , 4.5, 6. , 8. , 10. ]) > > > > thanks et cheers, > > > > Chao > > -- > > > *********************************************************************************** > > Chao YUE > > Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL) > > UMR 1572 CEA-CNRS-UVSQ > > Batiment 712 - Pe 119 > > 91191 GIF Sur YVETTE Cedex > > Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16 > > > ************************************************************************************ > > > > > > _______________________________________________ > > NumPy-Discussion mailing list > > [email protected] > > http://mail.scipy.org/mailman/listinfo/numpy-discussion > > > > > > -- > > Christopher Barker, Ph.D. > Oceanographer > > Emergency Response Division > NOAA/NOS/OR&R (206) 526-6959 voice > 7600 Sand Point Way NE (206) 526-6329 fax > Seattle, WA 98115 (206) 526-6317 main reception > > [email protected] > _______________________________________________ > NumPy-Discussion mailing list > [email protected] > http://mail.scipy.org/mailman/listinfo/numpy-discussion > -- *********************************************************************************** Chao YUE Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL) UMR 1572 CEA-CNRS-UVSQ Batiment 712 - Pe 119 91191 GIF Sur YVETTE Cedex Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16 ************************************************************************************
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