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bundles / numpy latest / numpy / savetxt

_ArrayFunctionDispatcher

numpy:savetxt

source: /dev/numpy/build-install/usr/lib/python3.14/site-packages/numpy/lib/_npyio_impl.py :1401

Signature

def   savetxt ( fname X fmt = %.18e delimiter = newline = header = '' footer = '' comments = # encoding = None )

Summary

Save an array to a text file.

Parameters

fname : filename, file handle or pathlib.Path

If the filename ends in .gz, the file is automatically saved in compressed gzip format. loadtxt understands gzipped files transparently.

X : 1D or 2D 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.

header : str, optional

String that will be written at the beginning of the file.

footer : str, optional

String that will be written at the end of the file.

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.

encoding : {None, str}, optional

Encoding used to encode the outputfile. Does not apply to output streams. If the encoding is something other than 'bytes' or 'latin1' you will not be able to load the file in NumPy versions < 1.14. Default is 'latin1'.

Notes

Further explanation of the fmt parameter (%[flag]width[.precision]specifier):

flags:

-left justify

+Forces to precede result with + or -.

0Left 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:

ccharacter

d or isigned decimal integer

e or Escientific notation with e or E.

fdecimal floating point

g,Guse the shorter of e,E or f

osigned octal

sstring of characters

uunsigned decimal integer

x,Xunsigned hexadecimal integer

This explanation of fmt is not complete, for an exhaustive specification see [1].

Examples

import numpy as np
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

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

Aliases

  • numpy.savetxt

Referenced by