using numpy.savetxt to save columns of numerical values and columns of text values
I have been unable to find a way of doing a very simple thing: saving data that contains both arrays of numerical values and arrays of string values, using savetxt in numpy. As a very simple example, suppose a is a numpy array of integers and b is one containing strings, e.g.: a = np.array([1,2,3]) b = np.array(['one', 'two', 'three']) The following call to savetxt: savetxt('test.txt', transpose((a,b)), fmt='%i %s') produces the following error: float argument required, not numpy.string_ I don't have any problems if I mix integers and floats in the format string, or save all values as strings, but I am completely unable to save formatted numerical values and strings in different columns using savetxt. There must be an easy solution! Thank you. Richard Beare
On Thu, Nov 26, 2009 at 11:30 PM, Richared Beare < richard.beare@sci.monash.edu.au> wrote:
I have been unable to find a way of doing a very simple thing: saving data that contains both arrays of numerical values and arrays of string values, using savetxt in numpy.
As a very simple example, suppose a is a numpy array of integers and b is one containing strings, e.g.:
a = np.array([1,2,3])
b = np.array(['one', 'two', 'three'])
The following call to savetxt:
savetxt('test.txt', transpose((a,b)), fmt='%i %s')
produces the following error:
float argument required, not numpy.string_
I don't have any problems if I mix integers and floats in the format string, or save all values as strings, but I am completely unable to save formatted numerical values and strings in different columns using savetxt.
There must be an easy solution!
Seemingly savetxt('test.txt', transpose((a,b)), fmt='%s %s') ; replacing the %i with %s works. However you can't control the output precision while saving the data into a file.
Thank you.
Richard Beare _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
-- Gökhan
On Fri, Nov 27, 2009 at 12:55 AM, Gökhan Sever <gokhansever@gmail.com> wrote:
On Thu, Nov 26, 2009 at 11:30 PM, Richared Beare <richard.beare@sci.monash.edu.au> wrote:
I have been unable to find a way of doing a very simple thing: saving data that contains both arrays of numerical values and arrays of string values, using savetxt in numpy.
As a very simple example, suppose a is a numpy array of integers and b is one containing strings, e.g.:
a = np.array([1,2,3])
b = np.array(['one', 'two', 'three'])
The following call to savetxt:
savetxt('test.txt', transpose((a,b)), fmt='%i %s')
produces the following error:
float argument required, not numpy.string_
In [14]: np.transpose((a,b)) Out[14]: array([['1', 'one'], ['2', 'two'], ['3', 'three']], dtype='|S8') The ints get cast to strings by transpose. You need a structured array. This works but there may be an easier way to build the array. ab = np.zeros(3, dtype=[('var1',float),('var2','a5')]) ab['var1'] = a ab['var2'] = b np.savetxt('test.txt', ab, fmt="%i %s") hth, Skipper
I don't have any problems if I mix integers and floats in the format string, or save all values as strings, but I am completely unable to save formatted numerical values and strings in different columns using savetxt.
There must be an easy solution!
Seemingly savetxt('test.txt', transpose((a,b)), fmt='%s %s') ; replacing the %i with %s works. However you can't control the output precision while saving the data into a file.
Thank you.
Richard Beare _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
-- Gökhan
_______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
participants (3)
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Gökhan Sever -
Richared Beare -
Skipper Seabold