Handle invalid fieldnames when parsing python dict to matlab via struct

Question

Benvaulter 2018-5-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/399639-handle-invalid-fieldnames-when-parsing-python-dict-to-matlab-via-struct

回答： Steven Lord 2018-5-8

I am trying to convert a python dict to a Matlab struct like so:

pyClass = py.someClass.someSubClass();
data = x.someFunction();
data = struct(data);

This usually works fine, however, Matlab throws the following error:

Error using py.dict/struct
Invalid field name "yyy/xxx"

I know that Matlab requires the following three conditions for fieldnames to be valid:

start with a letter, otherwise assigning to that field will error

contain only letters, numbers, and/or the underscore character, otherwise assigning to that field will error,

and must be no longer than namelengthmax (currently 63) characters, otherwise you will receive a warning and the field name will be truncated

Does anyone know how I can handle this error - i.e. have a small python function that I can call from within Matlab to remove invalid characters?

Here is a snippet of what the python dict looks like (in this case the "/" is the issue):

data = 
Python dict with no properties.
{'BTC/USD': {'fee_loaded': False, 'percentage': True, 'tierBased': True, 'maker': 0.001, 'taker': 0.002, 'tiers': {'taker': [[0, 0.002], ...
Thanks in advance!

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Benvaulter 2018-5-8

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/399639-handle-invalid-fieldnames-when-parsing-python-dict-to-matlab-via-struct#answer_319210

在 MATLAB Online 中打开

I solved the issue by coverting the dict within python to json and then outputting the json to matlab where I then decode the data to retrieve the final struct which works perfectly fine for me so far. Here is the solution that I came up with:

pyClass = py.someClass.someSubClass();
data = x.someFunction();
data = py.json.dumps(data);
data = char(data);
data = jsondecode(data);

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Rik 2018-5-8

If this indeed solves your problem, you can mark this as accepted answer

请先登录，再进行评论。

Answer 2

Steven Lord 2018-5-8

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/399639-handle-invalid-fieldnames-when-parsing-python-dict-to-matlab-via-struct#answer_319262

If you can get a list of the names in your dict object that you want to be the fieldnames in the MATLAB struct array, pass them through matlab.lang.makeValidName.