numpy.lib.format.open_memmap#
- lib.format.open_memmap(filename, mode='r+', dtype=None, shape=None, fortran_order=False, version=None, *, max_header_size=10000)[source]#
Open a .npy file as a memory-mapped array.
This may be used to read an existing file or create a new one.
- Parameters:
- filenamestr or path-like
The name of the file on disk. This may not be a file-like object.
- modestr, optional
The mode in which to open the file; the default is ‘r+’. In addition to the standard file modes, ‘c’ is also accepted to mean “copy on write.” See
memmap
for the available mode strings.- dtypedata-type, optional
The data type of the array if we are creating a new file in “write” mode, if not,
dtype
is ignored. The default value is None, which results in a data-type offloat64
.- shapetuple of int
The shape of the array if we are creating a new file in “write” mode, in which case this parameter is required. Otherwise, this parameter is ignored and is thus optional.
- fortran_orderbool, optional
Whether the array should be Fortran-contiguous (True) or C-contiguous (False, the default) if we are creating a new file in “write” mode.
- versiontuple of int (major, minor) or None
If the mode is a “write” mode, then this is the version of the file format used to create the file. None means use the oldest supported version that is able to store the data. Default: None
- max_header_sizeint, optional
Maximum allowed size of the header. Large headers may not be safe to load securely and thus require explicitly passing a larger value. See
ast.literal_eval
for details.
- Returns:
- marraymemmap
The memory-mapped array.
- Raises:
- ValueError
If the data or the mode is invalid.
- OSError
If the file is not found or cannot be opened correctly.
See also