发出ncks命令时出错，意外的字节对象而不是字符串

Question

当我为ncks发出一个NCO调用usign pynco时，我收到了一个错误，它看起来像是在发送一个字节对象，而不是一个字符串，结果是：

pydev debugger: starting (pid: 7864)
2018-02-05  11:30:53 INFO Start time:    2018-02-05 11:30:53.365789
Error in calling operator ncks with:
>>> C:/home/miniconda/pkgs/nco-4.7.1-vc14_0/Library/bin\ncks --dmn=lon,0,20,1 --output=C:/home/data/nclimgrid/work\nclimgrid_lowres_prcp_slice00.nc C:/home/data/nclimgrid/nclimgrid_lowres_prcp.nc <<<
Inputs: C:/home/data/nclimgrid/nclimgrid_lowres_prcp.nc
b''
2018-02-05  11:36:19 ERROR Failed to complete
Traceback (most recent call last):
  File "C:\Users\DELL\git\process_grid\process_grid.py", line 949, in <module>
    options=slice_option)
  File "C:\home\miniconda\lib\site-packages\nco\nco.py", line 277, in get
    raise NCOException(**retvals)
nco.nco.NCOException: (returncode:3221225781) b''
Traceback (most recent call last):
  File "C:\home\eclipse\neon\eclipse\plugins\org.python.pydev_6.2.0.201711281614\pysrc\pydevd.py", line 1621, in <module>
    main()
  File "C:\home\eclipse\neon\eclipse\plugins\org.python.pydev_6.2.0.201711281614\pysrc\pydevd.py", line 1615, in main
    globals = debugger.run(setup['file'], None, None, is_module)
  File "C:\home\eclipse\neon\eclipse\plugins\org.python.pydev_6.2.0.201711281614\pysrc\pydevd.py", line 1022, in run
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File
"C:\home\eclipse\neon\eclipse\plugins\org.python.pydev_6.2.0.201711281614\pysrc\_pydev_imps\_pydev_execfile.py", line 25, in execfile
    exec(compile(contents+"\n", file, 'exec'), glob, loc)
  File "C:\Users\DELL\git\process_grid\process_grid.py", line 949, in <module>
    options=slice_option)
  File "C:\home\miniconda\lib\site-packages\nco\nco.py", line 277, in get
    raise NCOException(**retvals)
nco.nco.NCOException: (returncode:3221225781) b'' 

发生这种情况的代码：

# assume the same longitude slice specs across temperature, precipitation, and soils files
slice_option = ['--dmn=lon,{0},{1},1'.format(precip_files[i][1], precip_files[i][2])]

# use NCO to slice the specified longitude range from the files
slice_file_precip = precip_files[i][0]
nco.ncks(input=args.precip_file, 
         output=slice_file_precip, 
         options=slice_option)

我可以调试到pynco代码中，并看到这是在nco.__getattr__.get()函数中发生的，当它进入其中时，传递给ncks二进制文件的cmd列表对象如下所示：

<class 'list'>: ['C:/home/miniconda/pkgs/nco-4.7.1-vc14_0/Library/bin\\ncks', 
                 '--dmn=lon,0,20,1', 
                 '--output=C:/home/data/nclimgrid/work\\nclimgrid_lowres_prcp_slice00.nc', 
                 'C:/home/data/nclimgrid/nclimgrid_lowres_prcp.nc']

错误消息似乎显示空的第二个输入，b''，也许这是被错误插入的，因为没有第二个输入文件？

哪里出了问题？

Answer 1

您对pyno的调用似乎是正确的。我无法在Linux机器上重现您的错误。而且我没有在windows上安装python。

有几件事你可以试一试

1. 直接运行ncks命令：

C:/home/miniconda/pkgs/nco-4.7.1-vc14_0/Library/bin\ncks --dmn=lon,0,20,1 --output=C:/home/data/nclimgrid/work\nclimgrid_lowres_prcp_slice00.nc C:/home/data/nclimgrid/nclimgrid_lowres_prcp.nc

• 尝试运行 pynco /中的测试模块通过在pynco目录中运行命令'py.test‘来执行此操作。您可能需要安装python模块'pytest'

...Henry