Re: [Numpy-discussion] Printing formatted numerical values
Is there a convention for dealing with NaN and Inf? I've found that
trusting the default behavior is a very bad idea:
---
from numpy import *
x = zeros((5,7))
x[:,3:] = nan
x[:,-1] = inf
savetxt('problem_array.txt',x,delimiter='\t')
x2 = loadtxt('problem_array.txt')
print(x.shape) # (5, 7)
print(x2.shape) # (5, 4)
print(x2[0,:])
print(open('problem_array.txt').readline().strip().split('\t'))
---
On my system the loaded array is reduced in size relative to the saved
array. Does savetxt need some conditionals to deal with special
values like these?
Jonathan
On Mon, Nov 15, 2010 at 8:44 AM, Dave Hirschfeld
wrote:
> math.duke.edu> writes:
>
>>
>> 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?
>>
>
> For stdout you can simply do:
>
> In [26]: w, x, y, z = np.randint(0,100,4)
>
> In [27]: type(w)
> Out[27]:
>
> In [28]: print("%f %g %e %d" % (w,x,y,z,))
> 68.00 64 1.30e+01 57
>
> In [29]: w, x, y, z
> Out[29]: (68, 64, 13, 57)
>
> For a file I would use np.savetxt
>
> HTH,
> Dave
>
>
>
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Re: [Numpy-discussion] Printing formatted numerical values
math.duke.edu> writes:
>
> 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?
>
For stdout you can simply do:
In [26]: w, x, y, z = np.randint(0,100,4)
In [27]: type(w)
Out[27]:
In [28]: print("%f %g %e %d" % (w,x,y,z,))
68.00 64 1.30e+01 57
In [29]: w, x, y, z
Out[29]: (68, 64, 13, 57)
For a file I would use np.savetxt
HTH,
Dave
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Re: [Numpy-discussion] Printing formatted numerical values
On Mon, Nov 15, 2010 at 08:32, wrote:
> 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?
Correct. On a 64-bit system, numpy.int32 does not subtype from int.
The format codes do strict type-checking.
--
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
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Re: [Numpy-discussion] Printing formatted numerical values
On 15 November 2010 15:32, wrote:
> 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?
Use the .tofile() method:
numpy.random.random(5).tofile(sys.stdout, ' ', '%s')
0.230466435867 0.609443784908 0.353855676828 0.552641723317 0.186418931597
(works only on "real files", afaik, not on StringIO or similar)
cheers,
Gerrit.
--
Exploring space at http://gerrit-explores.blogspot.com/
Personal homepage at http://www.topjaklont.org/
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[Numpy-discussion] Printing formatted numerical values
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]:
In [7]: print('{0:2d}'.format(w[0,0]))
ValueError? Traceback (most recent call last)
/home/p/o/dev/thesis/python/wavelet/ in ()
ValueError?: Unknown format code 'd' for object of type 'str'
--
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