em 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'.

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`` 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 [1]_.

References
----------
.. [1] `Format Specification Mini-Language
       <https://docs.python.org/library/string.html#format-specification-mini-language>`_,
       Python Documentation.

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

c