Function _write_array_header

numpy/lib/format.py:414–447

Write the header for an array and returns the version used Parameters ---------- fp : filelike object d : dict This has the appropriate entries for writing its string representation to the header of the file. version : tuple or None None means use oldest

(fp, d, version=None)

def _write_array_header(fp, d, version=None):
    """ Write the header for an array and returns the version used

    Parameters
    ----------
    fp : filelike object
    d : dict
        This has the appropriate entries for writing its string representation
        to the header of the file.
    version : tuple or None
        None means use oldest that works. Providing an explicit version will
        raise a ValueError if the format does not allow saving this data.
        Default: None
    """
    header = ["{"]
    for key, value in sorted(d.items()):
        # Need to use repr here, since we eval these when reading
        header.append("'%s': %s, " % (key, repr(value)))
    header.append("}")
    header = "".join(header)

    # Add some spare space so that the array header can be modified in-place
    # when changing the array size, e.g. when growing it by appending data at
    # the end.
    shape = d['shape']
    header += " " * ((GROWTH_AXIS_MAX_DIGITS - len(repr(
        shape[-1 if d['fortran_order'] else 0]
    ))) if len(shape) > 0 else 0)

    if version is None:
        header = _wrap_header_guess_version(header)
    else:
        header = _wrap_header(header, version)
    fp.write(header)

def write_array_header_1_0(fp, d):
    """ Write the header for an array using the 1.0 format.