def get_file_obj(fname, mode='r', encoding=None):
"""
Light wrapper to handle strings and let files (anything else) pass through.
It also handle '.gz' files.
Parameters
----------
fname: string or file-like object
File to open / forward
mode: string
Argument passed to the 'open' or 'gzip.open' function
encoding: string
For Python 3 only, specify the encoding of the file
Returns
-------
A file-like object that is always a context-manager. If the `fname`
was already a file-like object, the returned context manager
*will not close the file*.
"""
if _is_string_like(fname):
return _open(fname, mode, encoding)
try:
# Make sure the object has the write methods
if 'r' in mode:
assert hasattr(fname, 'read')
if 'w' in mode or 'a' in mode:
assert hasattr(fname, 'write')
except AssertionError: # pragma: no cover
raise ValueError('fname must be a string or a file-like object')
return EmptyContextManager(fname)
def drop_fields(base, drop_names, usemask=True, asrecarray=False):
"""
Return a new array with fields in `drop_names` dropped.
Nested fields are supported.
Parameters
----------
base : array
Input array
drop_names : string or sequence
String or sequence of strings corresponding to the names of the fields
to drop.
usemask : {False, True}, optional
Whether to return a masked array or not.
asrecarray : string or sequence
Whether to return a recarray or a mrecarray (`asrecarray=True`) or
a plain ndarray or masked array with flexible dtype (`asrecarray=False`)
Examples
--------
>>> a = np.array([(1, (2, 3.0)), (4, (5, 6.0))],
dtype=[('a', int), ('b', [('ba', float), ('bb', int)])])
>>> drop_fields(a, 'a')
array([((2.0, 3),), ((5.0, 6),)],
dtype=[('b', [('ba', '<f8'), ('bb', '<i4')])])
>>> drop_fields(a, 'ba')
array([(1, (3,)), (4, (6,))],
dtype=[('a', '<i4'), ('b', [('bb', '<i4')])])
>>> drop_fields(a, ['ba', 'bb'])
array([(1,), (4,)],
dtype=[('a', '<i4')])
"""
if _is_string_like(drop_names):
drop_names = [drop_names,]
else:
drop_names = set(drop_names)
#
def _drop_descr(ndtype, drop_names):
names = ndtype.names
newdtype = []
for name in names:
current = ndtype[name]
if name in drop_names:
continue
if current.names:
descr = _drop_descr(current, drop_names)
if descr:
newdtype.append((name, descr))
else:
newdtype.append((name, current))
return newdtype
#
newdtype = _drop_descr(base.dtype, drop_names)
if not newdtype:
return None
#
output = np.empty(base.shape, dtype=newdtype)
output = recursive_fill_fields(base, output)
return _fix_output(output, usemask=usemask, asrecarray=asrecarray)
def drop_fields(base, drop_names, usemask=True, asrecarray=False):
"""
Return a new array with fields in `drop_names` dropped.
Nested fields are supported.
Parameters
----------
base : array
Input array
drop_names : string or sequence
String or sequence of strings corresponding to the names of the fields
to drop.
usemask : {False, True}, optional
Whether to return a masked array or not.
asrecarray : string or sequence
Whether to return a recarray or a mrecarray (`asrecarray=True`) or
a plain ndarray or masked array with flexible dtype (`asrecarray=False`)
Examples
--------
>>> a = np.array([(1, (2, 3.0)), (4, (5, 6.0))],
dtype=[('a', int), ('b', [('ba', float), ('bb', int)])])
>>> drop_fields(a, 'a')
array([((2.0, 3),), ((5.0, 6),)],
dtype=[('b', [('ba', '<f8'), ('bb', '<i4')])])
>>> drop_fields(a, 'ba')
array([(1, (3,)), (4, (6,))],
dtype=[('a', '<i4'), ('b', [('bb', '<i4')])])
>>> drop_fields(a, ['ba', 'bb'])
array([(1,), (4,)],
dtype=[('a', '<i4')])
"""
if _is_string_like(drop_names):
drop_names = [drop_names,]
else:
drop_names = set(drop_names)
#
def _drop_descr(ndtype, drop_names):
names = ndtype.names
newdtype = []
for name in names:
current = ndtype[name]
if name in drop_names:
continue
if current.names:
descr = _drop_descr(current, drop_names)
if descr:
newdtype.append((name, descr))
else:
newdtype.append((name, current))
return newdtype
#
newdtype = _drop_descr(base.dtype, drop_names)
if not newdtype:
return None
#
output = np.empty(base.shape, dtype=newdtype)
output = recursive_fill_fields(base, output)
return _fix_output(output, usemask=usemask, asrecarray=asrecarray)
def get_file_obj(fname, mode='r', encoding=None):
"""
Light wrapper to handle strings and let files (anything else) pass through.
It also handle '.gz' files.
Parameters
==========
fname: string or file-like object
File to open / forward
mode: string
Argument passed to the 'open' or 'gzip.open' function
encoding: string
For Python 3 only, specify the encoding of the file
Returns
=======
A file-like object that is always a context-manager. If the `fname` was already a file-like object,
the returned context manager *will not close the file*.
"""
if _is_string_like(fname):
return _open(fname, mode, encoding)
try:
# Make sure the object has the write methods
if 'r' in mode:
fname.read
if 'w' in mode or 'a' in mode:
fname.write
except AttributeError:
raise ValueError('fname must be a string or a file-like object')
return EmptyContextManager(fname)
def get_file_obj(fname, mode="r", encoding=None):
"""
Light wrapper to handle strings, path objects and let files (anything else)
pass through.
It also handle '.gz' files.
Parameters
----------
fname : str, path object or file-like object
File to open / forward
mode : str
Argument passed to the 'open' or 'gzip.open' function
encoding : str
For Python 3 only, specify the encoding of the file
Returns
-------
A file-like object that is always a context-manager. If the `fname` was
already a file-like object, the returned context manager *will not
close the file*.
"""
if _is_string_like(fname):
fname = Path(fname)
if isinstance(fname, Path):
return fname.open(mode=mode, encoding=encoding)
elif hasattr(fname, "open"):
return fname.open(mode=mode, encoding=encoding)
try:
return open(fname, mode, encoding=encoding)
except TypeError:
try:
# Make sure the object has the write methods
if "r" in mode:
fname.read
if "w" in mode or "a" in mode:
fname.write
except AttributeError:
raise ValueError("fname must be a string or a file-like object")
return EmptyContextManager(fname)
def savetxt(fname, X, names=None, fmt='%.18e', delimiter=' '):
"""
Save an array to a text file.
This is just a copy of numpy.savetxt patched to support structured arrays
or a header of names. Does not include py3 support now in savetxt.
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.
names : list, optional
If given names will be the column header in the text file. If None and
X is a structured or recarray then the names are taken from
X.dtype.names.
fmt : str or sequence of strs
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.
delimiter : str
Character separating columns.
See Also
--------
save : Save an array to a binary file in NumPy ``.npy`` format
savez : Save several arrays into a ``.npz`` compressed archive
Notes
-----
Further explanation of the `fmt` parameter
(``%[flag]width[.precision]specifier``):
flags:
``-`` : left justify
``+`` : Forces to preceed 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
<http://docs.python.org/library/string.html#
format-specification-mini-language>`_, Python Documentation.
Examples
--------
>>> savetxt('test.out', x, delimiter=',') # x is an array
>>> savetxt('test.out', (x,y,z)) # x,y,z equal sized 1D arrays
>>> savetxt('test.out', x, fmt='%1.4e') # use exponential notation
"""
if _is_string_like(fname):
if fname.endswith('.gz'):
import gzip
fh = gzip.open(fname, 'wb')
else:
fh = file(fname, 'w')
elif hasattr(fname, 'seek'):
fh = fname
else:
raise ValueError('fname must be a string or file handle')
X = np.asarray(X)
# Handle 1-dimensional arrays
if X.ndim == 1:
# Common case -- 1d array of numbers
if X.dtype.names is None:
X = np.atleast_2d(X).T
ncol = 1
# Complex dtype -- each field indicates a separate column
else:
ncol = len(X.dtype.descr)
else:
ncol = X.shape[1]
# `fmt` can be a string with multiple insertion points or a list of formats.
# E.g. '%10.5f\t%10d' or ('%10.5f', '$10d')
if type(fmt) in (list, tuple):
if len(fmt) != ncol:
raise AttributeError('fmt has wrong shape. %s' % str(fmt))
format = delimiter.join(fmt)
elif type(fmt) is str:
if fmt.count('%') == 1:
fmt = [fmt, ]*ncol
format = delimiter.join(fmt)
elif fmt.count('%') != ncol:
raise AttributeError('fmt has wrong number of %% formats. %s'
% fmt)
else:
format = fmt
# handle names
if names is None and X.dtype.names:
names = X.dtype.names
if names is not None:
fh.write(delimiter.join(names) + '\n')
for row in X:
fh.write(format % tuple(row) + '\n')
def savetxt(fname, X, names=None, fmt='%.18e', delimiter=' '):
"""
Save an array to a text file.
This is just a copy of numpy.savetxt patched to support structured arrays
or a header of names. Does not include py3 support now in savetxt.
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.
names : list, optional
If given names will be the column header in the text file. If None and
X is a structured or recarray then the names are taken from
X.dtype.names.
fmt : str or sequence of strs
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.
delimiter : str
Character separating columns.
See Also
--------
save : Save an array to a binary file in NumPy ``.npy`` format
savez : Save several arrays into a ``.npz`` compressed archive
Notes
-----
Further explanation of the `fmt` parameter
(``%[flag]width[.precision]specifier``):
flags:
``-`` : left justify
``+`` : Forces to preceed 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
<http://docs.python.org/library/string.html#
format-specification-mini-language>`_, Python Documentation.
Examples
--------
>>> savetxt('test.out', x, delimiter=',') # x is an array
>>> savetxt('test.out', (x,y,z)) # x,y,z equal sized 1D arrays
>>> savetxt('test.out', x, fmt='%1.4e') # use exponential notation
"""
if _is_string_like(fname):
if fname.endswith('.gz'):
import gzip
fh = gzip.open(fname, 'wb')
else:
fh = file(fname, 'w')
elif hasattr(fname, 'seek'):
fh = fname
else:
raise ValueError('fname must be a string or file handle')
X = np.asarray(X)
# Handle 1-dimensional arrays
if X.ndim == 1:
# Common case -- 1d array of numbers
if X.dtype.names is None:
X = np.atleast_2d(X).T
ncol = 1
# Complex dtype -- each field indicates a separate column
else:
ncol = len(X.dtype.descr)
else:
ncol = X.shape[1]
# `fmt` can be a string with multiple insertion points or a list of formats.
# E.g. '%10.5f\t%10d' or ('%10.5f', '$10d')
if type(fmt) in (list, tuple):
if len(fmt) != ncol:
raise AttributeError('fmt has wrong shape. %s' % str(fmt))
format = delimiter.join(fmt)
elif type(fmt) is str:
if fmt.count('%') == 1:
fmt = [
fmt,
] * ncol
format = delimiter.join(fmt)
elif fmt.count('%') != ncol:
raise AttributeError('fmt has wrong number of %% formats. %s' %
fmt)
else:
format = fmt
# handle names
if names is None and X.dtype.names:
names = X.dtype.names
if names is not None:
fh.write(delimiter.join(names) + '\n')
for row in X:
fh.write(format % tuple(row) + '\n')
def savetxt_nice(fname,
X,
fmt='%.18e',
delimiter=' ',
newline='\n',
header='',
footer='',
comments='# '):
"""
Reimplmenentation of numpy's savetxt that doesn't complain about
bytes when saving to unicode files in Python 3.
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) a single specifier, `fmt='%.4e'`, resulting in numbers formatted
like `' (%s+%sj)' % (fmt, fmt)`
b) a full string specifying every real and imaginary part, e.g.
`' %.4e %+.4j %.4e %+.4j %.4e %+.4j'` for 3 columns
c) 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.
.. versionadded:: 1.5.0
header : str, optional
String that will be written at the beginning of the file.
.. versionadded:: 1.7.0
footer : str, optional
String that will be written at the end of the file.
.. versionadded:: 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``.
.. versionadded:: 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`` 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
<http://docs.python.org/library/string.html#
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
"""
# Py3 conversions first
if isinstance(fmt, bytes):
fmt = asstr(fmt)
delimiter = asstr(delimiter)
own_fh = False
if _is_string_like(fname):
own_fh = True
if fname.endswith('.gz'):
import gzip
fh = gzip.open(fname, 'wb')
else:
if sys.version_info[0] >= 3:
fh = open(fname, 'wb')
else:
fh = open(fname, 'w')
elif hasattr(fname, 'write'):
fh = fname
else:
raise ValueError('fname must be a string or file handle')
try:
X = np.asarray(X)
# Handle 1-dimensional arrays
if X.ndim == 1:
# Common case -- 1d array of numbers
if X.dtype.names is None:
X = np.atleast_2d(X).T
ncol = 1
# Complex dtype -- each field indicates a separate column
else:
ncol = len(X.dtype.descr)
else:
ncol = X.shape[1]
iscomplex_X = np.iscomplexobj(X)
# `fmt` can be a string with multiple insertion points or a
# list of formats. E.g. '%10.5f\t%10d' or ('%10.5f', '$10d')
if isinstance(fmt, (list, tuple)):
if len(fmt) != ncol:
raise AttributeError('fmt has wrong shape. %s' % str(fmt))
txt_format = asstr(delimiter).join(map(asstr, fmt))
elif isinstance(fmt, str):
n_fmt_chars = fmt.count('%')
error = ValueError('fmt has wrong number of %% formats: %s' % fmt)
if n_fmt_chars == 1:
if iscomplex_X:
fmt = [
' (%s+%sj)' % (fmt, fmt),
] * ncol
else:
fmt = [
fmt,
] * ncol
txt_format = delimiter.join(fmt)
elif iscomplex_X and n_fmt_chars != (2 * ncol):
raise error
elif ((not iscomplex_X) and n_fmt_chars != ncol):
raise error
else:
txt_format = fmt
else:
raise ValueError('invalid fmt: %r' % (fmt, ))
if len(header) > 0:
header = header.replace('\n', '\n' + comments)
fh.write(asbytes(comments + header + newline))
if iscomplex_X:
for row in X:
row2 = []
for number in row:
row2.append(number.real)
row2.append(number.imag)
fh.write(asbytes(txt_format % tuple(row2) + newline))
else:
for row in X:
try:
#print('txt_format = %r' % txt_format, type(txt_format))
fh.write(asbytes(txt_format % tuple(row) + newline))
except TypeError:
raise TypeError("Mismatch between array dtype ('%s') and "
"format specifier ('%s')" %
(str(X.dtype), txt_format))
if len(footer) > 0:
footer = footer.replace('\n', '\n' + comments)
fh.write(asbytes(comments + footer + newline))
finally:
if own_fh:
fh.close()
def savetxt_nice(fname, X, fmt='%.18e', delimiter=' ', newline='\n', header='',
footer='', comments='# ', encoding=None):
"""
Save an array to a text file. This is 95% a backport of numpy 1.15.1's
savetxt. It does not support:
- DataSource's URL
- pathlib fnames
- gz files
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 : 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.
.. versionadded:: 1.5.0
header : str, optional
String that will be written at the beginning of the file.
.. versionadded:: 1.7.0
footer : str, optional
String that will be written at the end of the file.
.. versionadded:: 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``.
.. versionadded:: 1.7.0
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'.
.. versionadded:: 1.14.0
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`` 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
<http://docs.python.org/library/string.html#
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
"""
# Py3 conversions first
if isinstance(fmt, bytes):
fmt = asstr(fmt)
delimiter = asstr(delimiter)
class WriteWrap:
"""Convert to unicode in py2 or to bytes on bytestream inputs."""
def __init__(self, fh, encoding):
self.fh = fh
self.encoding = encoding
self.do_write = self.first_write
def close(self):
self.fh.close()
def write(self, v):
self.do_write(v)
def write_bytes(self, v):
if isinstance(v, bytes):
self.fh.write(v)
else:
self.fh.write(v.encode(self.encoding))
def write_normal(self, v):
self.fh.write(asunicode(v))
def first_write(self, v):
try:
self.write_normal(v)
self.write = self.write_normal
except TypeError:
# input is probably a bytestream
self.write_bytes(v)
self.write = self.write_bytes
own_fh = False
#if is_pathlib_path(fname):
#fname = str(fname)
if _is_string_like(fname):
# datasource doesn't support creating a new file ...
open(fname, 'wt').close()
fh = open(fname, 'wt', encoding=encoding)
own_fh = True
# need to convert str to unicode for text io output
if sys.version_info[0] == 2:
fh = WriteWrap(fh, encoding or 'latin1')
elif hasattr(fname, 'write'):
# wrap to handle byte output streams
fh = WriteWrap(fname, encoding or 'latin1')
#if _is_string_like(fname):
#own_fh = True
#if fname.endswith('.gz'):
#import gzip
#fh = gzip.open(fname, 'wb')
#else:
#if sys.version_info[0] >= 3:
#fh = open(fname, 'wb')
#else:
#fh = open(fname, 'w')
#elif hasattr(fname, 'write'):
#fh = fname
else:
raise ValueError('fname must be a string or file handle')
try:
X = np.asarray(X)
# Handle 1-dimensional arrays
if X.ndim == 0 or X.ndim > 2:
raise ValueError(
"Expected 1D or 2D array, got %dD array instead" % X.ndim)
elif X.ndim == 1:
# Common case -- 1d array of numbers
if X.dtype.names is None:
X = np.atleast_2d(X).T
ncol = 1
# Complex dtype -- each field indicates a separate column
else:
ncol = len(X.dtype.descr)
else:
ncol = X.shape[1]
iscomplex_X = np.iscomplexobj(X)
# `fmt` can be a string with multiple insertion points or a
# list of formats. E.g. '%10.5f\t%10d' or ('%10.5f', '$10d')
if isinstance(fmt, (list, tuple)):
if len(fmt) != ncol:
raise AttributeError('fmt has wrong shape. %s' % str(fmt))
txt_format = asstr(delimiter).join(map(asstr, fmt))
elif isinstance(fmt, str):
n_fmt_chars = fmt.count('%')
error = ValueError('fmt has wrong number of %% formats: %s' % fmt)
if n_fmt_chars == 1:
if iscomplex_X:
fmt = [' (%s+%sj)' % (fmt, fmt), ] * ncol
else:
fmt = [fmt, ] * ncol
txt_format = delimiter.join(fmt)
elif iscomplex_X and n_fmt_chars != (2 * ncol):
raise error
elif ((not iscomplex_X) and n_fmt_chars != ncol):
raise error
else:
txt_format = fmt
else:
raise ValueError('invalid fmt: %r' % (fmt,))
if len(header) > 0:
header = header.replace('\n', '\n' + comments)
fh.write(comments + header + newline)
if iscomplex_X:
for row in X:
row2 = []
for number in row:
row2.append(number.real)
row2.append(number.imag)
s = txt_format % tuple(row2) + newline
fh.write(s.replace('+-', '-'))
else:
for row in X:
try:
v = txt_format % tuple(row) + newline
except TypeError:
raise TypeError("Mismatch between array dtype ('%s') and "
"format specifier ('%s')"
% (str(X.dtype), txt_format))
fh.write(v)
if len(footer) > 0:
footer = footer.replace('\n', '\n' + comments)
fh.write(comments + footer + newline)
finally:
if own_fh:
fh.close()
def loadtxt(fname, dtype=float, comments='#', delimiter=None, converters=None,
skiprows=0, usecols=None, unpack=False,count = -1):
"""
Load data from a text file.
Each row in the text file must have the same number of values.
Parameters
----------
fname : file or string
File or filename to read. If the filename extension is ``.gz`` or
``.bz2``, the file is first decompressed.
dtype : data-type
Data type of the resulting array. If this is a record data-type,
the resulting array will be 1-dimensional, and each row will be
interpreted as an element of the array. In this case, the number
of columns used must match the number of fields in the data-type.
comments : string, optional
The character used to indicate the start of a comment.
delimiter : string, optional
The string used to separate values. By default, this is any
whitespace.
converters : {}
A dictionary mapping column number to a function that will convert
that column to a float. E.g., if column 0 is a date string:
``converters = {0: datestr2num}``. Converters can also be used to
provide a default value for missing data:
``converters = {3: lambda s: float(s or 0)}``.
skiprows : int
Skip the first `skiprows` lines.
usecols : sequence
Which columns to read, with 0 being the first. For example,
``usecols = (1,4,5)`` will extract the 2nd, 5th and 6th columns.
unpack : bool
If True, the returned array is transposed, so that arguments may be
unpacked using ``x, y, z = loadtxt(...)``
Returns
-------
out : ndarray
Data read from the text file.
See Also
--------
scipy.io.loadmat : reads Matlab(R) data files
Examples
--------
>>> from StringIO import StringIO # StringIO behaves like a file object
>>> c = StringIO("0 1\\n2 3")
>>> np.loadtxt(c)
array([[ 0., 1.],
[ 2., 3.]])
>>> d = StringIO("M 21 72\\nF 35 58")
>>> np.loadtxt(d, dtype={'names': ('gender', 'age', 'weight'),
... 'formats': ('S1', 'i4', 'f4')})
array([('M', 21, 72.0), ('F', 35, 58.0)],
dtype=[('gender', '|S1'), ('age', '<i4'), ('weight', '<f4')])
>>> c = StringIO("1,0,2\\n3,0,4")
>>> x,y = np.loadtxt(c, delimiter=',', usecols=(0,2), unpack=True)
>>> x
array([ 1., 3.])
>>> y
array([ 2., 4.])
"""
user_converters = converters
if usecols is not None:
usecols = list(usecols)
isstring = False
if _is_string_like(fname):
isstring = True
if fname.endswith('.gz'):
import gzip
fh = seek_gzip_factory(fname)
elif fname.endswith('.bz2'):
import bz2
fh = bz2.BZ2File(fname)
else:
fh = file(fname)
elif hasattr(fname, 'readline'):
fh = fname
else:
raise ValueError('fname must be a string or file handle')
X = []
def flatten_dtype(dt):
"""Unpack a structured data-type."""
if dt.names is None:
return [dt]
else:
types = []
for field in dt.names:
tp, bytes = dt.fields[field]
flat_dt = flatten_dtype(tp)
types.extend(flat_dt)
return types
def split_line(line):
"""Chop off comments, strip, and split at delimiter."""
line = line.split(comments)[0].strip()
if line:
return line.split(delimiter)
else:
return []
try:
# Make sure we're dealing with a proper dtype
dtype = np.dtype(dtype)
defconv = _getconv(dtype)
# Skip the first `skiprows` lines
for i in xrange(skiprows):
fh.readline()
# Read until we find a line with some values, and use
# it to estimate the number of columns, N.
first_vals = None
while not first_vals:
first_line = fh.readline()
if first_line == '': # EOF reached
raise IOError('End-of-file reached before encountering data.')
first_vals = split_line(first_line)
N = len(usecols or first_vals)
dtype_types = flatten_dtype(dtype)
if len(dtype_types) > 1:
# We're dealing with a structured array, each field of
# the dtype matches a column
converters = [_getconv(dt) for dt in dtype_types]
else:
# All fields have the same dtype
converters = [defconv for i in xrange(N)]
# By preference, use the converters specified by the user
for i, conv in (user_converters or {}).iteritems():
if usecols:
try:
i = usecols.index(i)
except ValueError:
# Unused converter specified
continue
converters[i] = conv
# Parse each line, including the first
vals_gen = ( split_line(line) for line in itertools.chain([first_line], fh) )
if usecols:
vals_gen = ( [x for i,x in enumerate(vals) if i in usecols] for vals in vals_gen )
data_gen = ( tuple([conv(val) for (conv, val) in zip(converters, vals)]) for vals in vals_gen if len(vals)>0 )
if len(dtype_types) > 1:
X = np.fromiter(data_gen, dtype = np.dtype([('', t) for t in dtype_types]),count=count)
X = X.view(dtype)
else:
X = np.fromiter(itertools.chain(*data_gen), dtype = dtype,count=count)
X.shape = (-1,N)
finally:
if isstring:
fh.close()
X = np.squeeze(X)
if unpack:
return X.T
else:
return X
