pathwaycom/pathway · error · ValueError

statistical.diff(): Invalid column reference for the paramet

Error message

statistical.diff(): Invalid column reference for the parameter timestamp.

What it means

Error "statistical.diff(): Invalid column reference for the parameter timestamp." thrown in pathwaycom/pathway.

Source

Thrown at python/pathway/stdlib/ordered/diff.py:93

    >>> pw.debug.compute_and_print(table, include_id=False)
    timestamp | instance | values | diff_values
    1         | 0        | 1      |
    2         | 1        | 2      |
    3         | 0        | 7      | 6
    3         | 1        | 4      | 2
    6         | 0        | 16     | 9
    6         | 1        | 11     | 7
    """

    if isinstance(timestamp, pw.ColumnReference):
        timestamp = self[timestamp]
    else:
        if isinstance(timestamp, str):
            raise ValueError(
                "statistical.diff(): Invalid column reference for the parameter timestamp,"
                + f" found a string. Did you mean this.{timestamp} instead of {repr(timestamp)}?"
            )
        raise ValueError(
            "statistical.diff(): Invalid column reference for the parameter timestamp."
        )

    ordered_table = self.sort(key=timestamp, instance=instance)

    for value in values:
        if isinstance(value, pw.ColumnReference):
            value = self[value]
        else:
            if isinstance(value, str):
                raise ValueError(
                    "statistical.diff(): Invalid column reference for the parameter value,"
                    + f" found a string. Did you mean this.{value} instead of {repr(value)}?"
                )
            raise ValueError(
                "statistical.diff(): Invalid column reference for the parameter value."
            )

View on GitHub (pinned to fa2f74a464)

Solutions

1. Pass a ColumnReference for the timestamp parameter, e.g. this.timestamp or <table>.timestamp.

Example fix

pw.stdlib.statistical.diff(this.timestamp, this.value)

When it happens

Trigger: Thrown at python/pathway/stdlib/ordered/diff.py:93 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of pathwaycom/pathway@fa2f74a464 (2026-08-15). Data as JSON: /api/errors/d663c2005cb23c94. Report an issue: GitHub.