NumPy: Input and output routines

Input and output routines

NumPy binary files (NPY, NPZ)
Name Description Syntax
load() Load arrays or pickled objects from .npy, .npz or pickled files. numpy.load(file, mmap_mode=None, allow_pickle=True, fix_imports=True,
save() Save an array to a binary file in NumPy .npy format. numpy.save(file, arr, allow_pickle=True, fix_imports=True)
savez() Save several arrays into a single file in uncompressed .npz format. numpy.savez(file, *args, **kwds)
savez_compressed() Save several arrays into a single file in compressed .npz format. numpy.savez_compressed(file, *args, **kwds)
Text files
Name Description Syntax
loadtxt() Load data from a text file. numpy.loadtxt(fname, dtype=<class 'float'>, comments='#', delimiter=None,
converters=None, skiprows=0, usecols=None, unpack=False, ndmin=0, encoding='bytes')
savetxt() Save an array to a text file. numpy.savetxt(fname, X, fmt='%.18e', delimiter=' ', newline='\n', header='', footer='',
comments='# ', encoding=None)
genfromtxt() Load data from a text file, with missing values handled as specified. numpy.genfromtxt(fname, dtype=<class 'float'>, comments='#', delimiter=None, skip_header=0, skip_footer=0, converters=None, missing_values=None, filling_values=None, usecols=None, names=None, excludelist=None, deletechars=None, replace_space='_', autostrip=False, case_sensitive=True, defaultfmt='f%i', unpack=None, usemask=False, loose=True, invalid_raise=True, max_rows=None, encoding='bytes')
fromregex() Construct an array from a text file, using regular expression parsing. numpy.fromregex(file, regexp, dtype, encoding=None)
fromstring() A new 1-D array initialized from raw binary or text data in a string. numpy.fromstring(string, dtype=float, count=-1, sep='')
ndarray.tofile() Write array to a file as text or binary (default). ndarray.tofile(fid, sep="", format="%s")
ndarray.tolist() Return the array as a (possibly nested) list ndarray.tolist()
Raw binary files
Name Description Syntax
fromfile() Construct an array from data in a text or binary file. numpy.fromfile(file, dtype=float, count=-1, sep='')
String formatting
Name Description Syntax
array2string() Return a string representation of an array. numpy.array2string(a, max_line_width=None, precision=None, suppress_small=None, separator=' ', prefix='', style=<no value>, formatter=None, threshold=None, edgeitems=None, sign=None, floatmode=None, suffix='', **kwarg)
array_repr() Return the string representation of an array. numpy.array_repr(arr, max_line_width=None, precision=None, suppress_small=None)
array_str() Return a string representation of the data in an array. numpy.array_str(a, max_line_width=None, precision=None, suppress_small=None)
format_float_positional() Format a floating-point scalar as a decimal string in positional notation. numpy.format_float_positional(x, precision=None, unique=True, fractional=True, trim='k',
sign=False, pad_left=None, pad_right=None)
format_float_scientific() Format a floating-point scalar as a decimal string in scientific notation. numpy.format_float_scientific(x, precision=None, unique=True, trim='k',
sign=False, pad_left=None, exp_digits=None)
Memory mapping files
Name Description Syntax
memmap() Create a memory-map to an array stored in a binary file on disk. class numpy.memmap
Text formatting options
set_printoptions() Set printing options. numpy.set_printoptions(precision=None, threshold=None, edgeitems=None, linewidth=None,
suppress=None, nanstr=None, infstr=None, formatter=None, sign=None, floatmode=None, **kwarg)
get_printoptions() Return the current print options. numpy.get_printoptions()
set_string_function() Set a Python function to be used when pretty printing arrays. numpy.set_string_function(f, repr=True)
printoptions() Context manager for setting print options. numpy.printoptions(*args, **kwargs)
Base-n representations
Name Description Syntax
binary_repr() Return the binary representation of the input number as a string. numpy.binary_repr(num, width=None)
base_repr() Return a string representation of a number in the given base system. numpy.base_repr(number, base=2, padding=0)
Data sources
DataSource() A generic data source file (file, http, ftp, ...). class numpy.DataSource(destpath='.')
Binary Format Description
lib.format() A simple format for saving numpy arrays to disk with the full information about them.  

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