141 lines
4.2 KiB
Python
141 lines
4.2 KiB
Python
"""
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Input/Output tools for working with binary data.
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See Also
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--------
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numpy.lib.io
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"""
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import numpy as np
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from statsmodels.iolib.openfile import get_file_obj
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def savetxt(fname, X, names=None, fmt='%.18e', delimiter=' '):
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"""
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Save an array to a text file.
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This is just a copy of numpy.savetxt patched to support structured arrays
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or a header of names. Does not include py3 support now in savetxt.
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Parameters
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----------
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fname : filename or file handle
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If the filename ends in ``.gz``, the file is automatically saved in
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compressed gzip format. `loadtxt` understands gzipped files
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transparently.
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X : array_like
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Data to be saved to a text file.
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names : list, optional
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If given names will be the column header in the text file.
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fmt : str or sequence of strs
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A single format (%10.5f), a sequence of formats, or a
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multi-format string, e.g. 'Iteration %d -- %10.5f', in which
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case `delimiter` is ignored.
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delimiter : str
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Character separating columns.
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See Also
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--------
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save : Save an array to a binary file in NumPy ``.npy`` format
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savez : Save several arrays into a ``.npz`` compressed archive
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Notes
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-----
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Further explanation of the `fmt` parameter
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(``%[flag]width[.precision]specifier``):
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flags:
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``-`` : left justify
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``+`` : Forces to preceed result with + or -.
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``0`` : Left pad the number with zeros instead of space (see width).
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width:
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Minimum number of characters to be printed. The value is not truncated
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if it has more characters.
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precision:
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- For integer specifiers (eg. ``d,i,o,x``), the minimum number of
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digits.
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- For ``e, E`` and ``f`` specifiers, the number of digits to print
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after the decimal point.
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- For ``g`` and ``G``, the maximum number of significant digits.
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- For ``s``, the maximum number of characters.
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specifiers:
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``c`` : character
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``d`` or ``i`` : signed decimal integer
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``e`` or ``E`` : scientific notation with ``e`` or ``E``.
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``f`` : decimal floating point
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``g,G`` : use the shorter of ``e,E`` or ``f``
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``o`` : signed octal
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``s`` : str of characters
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``u`` : unsigned decimal integer
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``x,X`` : unsigned hexadecimal integer
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This explanation of ``fmt`` is not complete, for an exhaustive
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specification see [1]_.
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References
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----------
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.. [1] `Format Specification Mini-Language
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<http://docs.python.org/library/string.html#
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format-specification-mini-language>`_, Python Documentation.
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Examples
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--------
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>>> savetxt('test.out', x, delimiter=',') # x is an array
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>>> savetxt('test.out', (x,y,z)) # x,y,z equal sized 1D arrays
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>>> savetxt('test.out', x, fmt='%1.4e') # use exponential notation
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"""
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with get_file_obj(fname, 'w') as fh:
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X = np.asarray(X)
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# Handle 1-dimensional arrays
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if X.ndim == 1:
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# Common case -- 1d array of numbers
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if X.dtype.names is None:
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X = np.atleast_2d(X).T
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ncol = 1
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# Complex dtype -- each field indicates a separate column
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else:
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ncol = len(X.dtype.descr)
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else:
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ncol = X.shape[1]
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# `fmt` can be a string with multiple insertion points or a list of formats.
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# E.g. '%10.5f\t%10d' or ('%10.5f', '$10d')
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if isinstance(fmt, (list, tuple)):
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if len(fmt) != ncol:
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raise AttributeError('fmt has wrong shape. %s' % str(fmt))
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format = delimiter.join(fmt)
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elif isinstance(fmt, str):
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if fmt.count('%') == 1:
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fmt = [fmt, ]*ncol
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format = delimiter.join(fmt)
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elif fmt.count('%') != ncol:
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raise AttributeError('fmt has wrong number of %% formats. %s'
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% fmt)
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else:
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format = fmt
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# handle names
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if names is None and X.dtype.names:
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names = X.dtype.names
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if names is not None:
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fh.write(delimiter.join(names) + '\n')
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for row in X:
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fh.write(format % tuple(row) + '\n')
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