nlcpy.loadtxt

nlcpy.loadtxt(fname, dtype=<class 'float'>, comments='#', delimiter=None, converters=None, skiprows=0, usecols=None, unpack=False, ndmin=0, encoding='bytes', max_rows=None)

Loads data from a text file.

Each row in the text file must have the same number of values.

Parameters

fnamefile or str or pathlib.Path

File, filename, or generator to read. If the filename extension is .gz or .bz2, the file is first decompressed. Note that generators should return byte strings for Python 3k.

dtypedtype, optional

Data-type of the resulting array; default: float.

commentsstr or sequence of str, optional

The characters or list of characters used to indicate the start of a comment. None implies no comments. For backwards compatibility, byte strings will be decoded as ‘latin1’. The default is ‘#’.

delimiterstr, optional

The string used to separate values. For backwards compatibility, byte strings will be decoded as ‘latin1’. The default is whitespace.

convertersdict, optional

A dictionary mapping column number to a function that will parse the column string into the desired value. 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.strip() or 0)}. Default: None.

skiprowsint, optional

Skip the first skiprows lines, including comments; default: 0.

usecolsint or sequence, optional

Which columns to read, with 0 being the first. For example, usecols = (1,4,5) will extract the 2nd, 5th and 6th columns. The default, None, results in all columns being read.

unpackbool, optional

If True, the returned array is transposed, so that arguments may be unpacked using x, y, z = loadtxt(...). Default is False.

ndminint, optional

The returned array will have at least ndmin dimensions. Otherwise mono-dimensional axes will be squeezed. Legal values: 0 (default), 1 or 2.

encodingstr, optional

Encoding used to decode the inputfile. Does not apply to input streams. The special value ‘bytes’ enables backward compatibility workarounds that ensures you receive byte arrays as results if possible and passes ‘latin1’ encoded strings to converters. Override this value to receive unicode arrays and pass strings as input to converters. If set to None the system default is used. The default value is ‘bytes’.

max_rowsint, optional

Read max_rows lines of content after skiprows lines. The default is to read all the lines.

Returns

outndarray

Data read from the text file.

See also

load

Loads arrays or pickled objects from .npy, .npz or pickled files.

Note

This function aims to be a fast reader for simply formatted files. The strings produced by the Python float.hex method can be used as input for floats.

Examples

>>> import nlcpy as vp
>>> from io import StringIO   # StringIO behaves like a file object
>>> c = StringIO(u"0 1\n2 3")
>>> vp.loadtxt(c)
array([[0., 1.],
       [2., 3.]])
>>> c = StringIO(u"1,0,2\n3,0,4")
>>> x, y = vp.loadtxt(c, delimiter=',', usecols=(0, 2), unpack=True)
>>> x
array([1., 3.])
>>> y
array([2., 4.])