[Numpy-discussion] Printing formatted numerical values
pv+numpy at math.duke.edu
pv+numpy at math.duke.edu
Mon Nov 15 09:32:34 EST 2010
Hi, what is the best way to print (to a file or to stdout) formatted
numerical values? Analogously to C's printf("%d %g",x,y) etc?
Numpy Documentation only discusses input *from* a file, or output of
entire arrays. (np.savetxt()) I just want tab or space-delimited output of
selected formatted values.
In the absence of numpy documentation on this matter, I tried to follow
python documentation and find errors. Below is ipython
-pylab transcript, which apparently complains that an int32 variable is
an object of type 'str'. How should I understand this? Does python not
understand that numpy.int32 is an integer?
Thank you!
In [2] import numpy as np
In [3]: w = np.arange (1,5,dtype=np.int32).reshape((2,2))
In [4]: w Out[4]: array([[1, 2],
[3, 4]], dtype=int32)
In [5]: w[0,0]
Out[5]: 1
In [6]: w[0,0].class Out[6]: <type 'numpy.int32'>
In [7]: print('{0:2d}'.format(w[0,0]))
ValueError? Traceback (most recent call last)
/home/p/o/dev/thesis/python/wavelet/<ipython console> in <module>()
ValueError?: Unknown format code 'd' for object of type 'str'
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