numpy.savetxt — NumPy v1.11 Manual (original) (raw)
numpy.savetxt(fname, X, fmt='%.18e', delimiter=' ', newline='\n', header='', footer='', comments='# ')[source]¶
Save an array to a text file.
| Parameters: | fname : filename or file handle If the filename ends in .gz, the file is automatically saved in compressed gzip format. loadtxt understands gzipped files transparently. X : array_like Data to be saved to a text file. fmt : str or sequence of strs, optional A single format (%10.5f), a sequence of formats, or a multi-format string, e.g. ‘Iteration %d – %10.5f’, in which case delimiter is ignored. For complex X, the legal options for fmt are: a single specifier, fmt=’%.4e’, resulting in numbers formatted like ‘ (%s+%sj)’ % (fmt, fmt) a full string specifying every real and imaginary part, e.g. ‘ %.4e %+.4j %.4e %+.4j %.4e %+.4j’ for 3 columns a list of specifiers, one per column - in this case, the real and imaginary part must have separate specifiers, e.g. [‘%.3e + %.3ej’, ‘(%.15e%+.15ej)’] for 2 columns delimiter : str, optional String or character separating columns. newline : str, optional String or character separating lines. New in version 1.5.0. header : str, optional String that will be written at the beginning of the file. New in version 1.7.0. footer : str, optional String that will be written at the end of the file. New in version 1.7.0. comments : str, optional String that will be prepended to the header and footer strings, to mark them as comments. Default: ‘# ‘, as expected by e.g.numpy.loadtxt. New in version 1.7.0. |
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See also
Save an array to a binary file in NumPy .npy format
Save several arrays into an uncompressed .npz archive
Save several arrays into a compressed .npz archive
Notes
Further explanation of the fmt parameter (%[flag]width[.precision]specifier):
flags:
- : left justify
- : Forces to precede result with + or -.
0 : Left pad the number with zeros instead of space (see width).
width:
Minimum number of characters to be printed. The value is not truncated if it has more characters.
precision:
- For integer specifiers (eg. d,i,o,x), the minimum number of digits.
- For e, E and f specifiers, the number of digits to print after the decimal point.
- For g and G, the maximum number of significant digits.
- For s, the maximum number of characters.
specifiers:
c : character
d or i : signed decimal integer
e or E : scientific notation with e or E.
f : decimal floating point
g,G : use the shorter of e,E or f
o : signed octal
s : string of characters
u : unsigned decimal integer
x,X : unsigned hexadecimal integer
This explanation of fmt is not complete, for an exhaustive specification see [R280].
References
| [R280] | (1, 2) Format Specification Mini-Language, Python Documentation. |
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Examples
x = y = z = np.arange(0.0,5.0,1.0) np.savetxt('test.out', x, delimiter=',') # X is an array np.savetxt('test.out', (x,y,z)) # x,y,z equal sized 1D arrays np.savetxt('test.out', x, fmt='%1.4e') # use exponential notation