Awesome question—let’s break this down step by step to make sense of what’s going on here.

Your workaround is totally valid #

You’re spot-on about why the double serialization happens: df.to_json(orient='table') returns a fully formed JSON string. When you drop that string directly into your parent dictionary and run json.dumps(), Python treats it as plain text—so it gets escaped into that nested, quoted mess like "{\"schema\": ..., \"data\": ...}". Using json.loads(df.to_json(orient='table')) to convert that string to a native Python dictionary first is the correct fix; it ensures the table structure integrates cleanly into your top-level JSON object instead of being treated as a single string value.

Why df.to_dict(orient='table') isn’t supported #

Pandas’ to_dict method is built to convert DataFrames into simple, native Python data structures (dictionaries, lists, series) using straightforward mappings. The orient options it supports (dict, list, series, split, records, index) all map directly to how you might intuitively represent a DataFrame’s rows and columns with basic Python types.

The 'table' orient, though? That’s a special case exclusive to to_json. It’s designed to produce output that follows the JSON Table Schema standard, which includes extra metadata (like column data types) in the schema field alongside the raw row data. This structure is purpose-built for JSON serialization, not for generic Python dictionary use cases.

Pandas developers likely didn’t add a 'table' option to to_dict because:

• The same result is easily achievable with json.loads(df.to_json(orient='table'))—no need to duplicate the logic in to_dict.
• The JSON Table Schema structure is more complex than the lightweight mappings to_dict was originally designed to handle, and it’s tightly tied to JSON output rather than native Python data structures.

Is this the right place to ask? #

Absolutely! Stack Overflow is an ideal spot for this kind of pandas-specific design question. You’ll find plenty of experienced pandas users (and even core contributors) who can offer deeper context or alternative approaches. Just make sure to frame your question clearly: explain your end goal, the double serialization problem you ran into, your current workaround, and your question about the missing to_dict option.

内容的提问来源于stack exchange，提问作者jonnybolton16