​

module  pixeltable.functions.json

import pixeltable as pxt
import pixeltable.functions as pxtf

t = pxt.get_table(...)
t.select(pxtf.json.make_list(t.json_col)).collect()

​

iterator  list_iterator()

@pxt.iterator
list_iterator(elements: pxt.Json[(Json = None, *, mode: pxt.String = 'strict', **kwargs)

• If a single positional argument is specified, as in list_iterator(t.col), then the elements of t.col must contain lists of dictionaries with matching signatures (identical keys and compatible value types). The iterator will yield one new column for each key in the dictionaries, and one output row per element in the lists.
• If multiple keyword arguments are specified, as in list_iterator(val_1=t.col_1, val_2=t.col_2), then the elements of each input column must contain lists, but not necessarily lists of dictionaries. The iterator will yield one new column for each keyword argument, zipping together the individual lists.

• elements (pxt.Json[(Json): A list of dictionaries to iterate over. The dictionary keys will be used as column names in the output. Cannot be specified together with keyword arguments.
• mode (Any): Only applies when called with keyword arguments. Determines how to handle lists of different lengths:
  • 'strict': Raises an error if the input lists have different lengths.
  • 'truncated': Iterates until the shortest input list is exhausted, ignoring any remaining elements in longer lists.
  • 'padded': Iterates until the longest input list is exhausted, yielding None for any missing elements from shorter lists.
• **kwargs (Any): One or more lists to iterate over. The kwarg names will be used as column names in the output. Cannot be specified together with elements.

​

uda  make_list()

@pxt.uda
make_list(*args, **kwargs) -> pxt.Json[(Json, ...)]

​

udf  dumps()

@pxt.udf
dumps(obj: pxt.Json) -> pxt.String

• obj (pxt.Json): A JSON-serializable object (dict, list, or scalar).

• pxt.String: A JSON-formatted string.