hi,all I have tried to use write_array() to write a float type array, some elements are "%f" type and some are "%e" type. Because the file should be read in another program which use "%e" as format, so .. it does wrong. Is it possible to write an array with exactly "C" or "Fortran" format to a file? I have tried ScientificPython, which offers Scientific.IO.FotranFormat(). but it seems doesn't work in python 2.3.4. help please Zhang yunfeng