numpy.savetxt¶
-
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 %+.4ej %.4e %+.4ej %.4e %+.4ej’ 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
andfooter
strings, to mark them as comments. Default: ‘# ‘, as expected by e.g.numpy.loadtxt
.New in version 1.7.0.
See also
save
- Save an array to a binary file in NumPy
.npy
format savez
- Save several arrays into an uncompressed
.npz
archive savez_compressed
- 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
andf
specifiers, the number of digits to print after the decimal point. - For
g
andG
, the maximum number of significant digits. - For
s
, the maximum number of characters.
- For integer specifiers (eg.
- specifiers:
c
: characterd
ori
: signed decimal integere
orE
: scientific notation withe
orE
.f
: decimal floating pointg,G
: use the shorter ofe,E
orf
o
: signed octals
: string of charactersu
: unsigned decimal integerx,X
: unsigned hexadecimal integer
This explanation of
fmt
is not complete, for an exhaustive specification see [R285].References
[R285] (1, 2) Format Specification Mini-Language, Python Documentation. 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