Fortio

A Python IO for Fortran Unformatted Binary Files with Variable-Length Records.

Features

read and write Fortran unformatted file
auto-detect endianness(byteorder)
allow reading data into pre-allocated buffers
allow skipping over records or jumping to wanted record directly without reading data
support subrecords (which is necessary for long record whose size larger than 4GB with signed 4 bytes integer header)
support numpy.memmap array for fast loading

pip install fortio

from fortio import FortranFile
with FortranFile(filename) as f:
    a = f.read_record('i4')
    f.skip_record()
    b = f.read_record('f8')

Read file that contains subrecords (e.g., records greater than 4GB) by setting signed header,

with FortranFile(filename, header_dtype='int32') as f:
    ...

Please read the docstring of FortranFile for detailed documentation.

FortranFile(filename, mode='r', header_dtype='uint32', auto_endian=True, check_file=True)
methods
- write_record(data)
- read_record(dtype='byte', shape=None, rec=None, memmap=False)
- mmap_record(dtype='byte', shape=None, rec=None)
- read_record_into(into, offset=None, rec=None)
- get_record_size(rec=None)
- skip_record(nrec=1)
- goto_record(rec=None)
- close()
- flush()
properties
- file
- filesize
- mode
- header_dtype
- long_records
- closed
- byteorder
internal properties and methods
- _fp
- _offsets
- _lengths
- _read_header()
- _check_byteorder()
- _check_file()
- _read_record_data(data)