microsoft/qlib · error · ValueError

metric must be dict or pd.Series

Error message

metric must be dict or pd.Series

What it means

Error "metric must be dict or pd.Series" thrown in microsoft/qlib.

Source

Thrown at qlib/backtest/high_performance_ds.py:517

        elif isinstance(other, self.__class__):
            return self.__class__(self.metric < other.metric)
        else:
            return NotImplemented

    def __len__(self):
        return len(self.metric)


class PandasSingleMetric(SingleMetric):
    """Each SingleMetric is based on pd.Series."""

    def __init__(self, metric: Union[dict, pd.Series] = {}):
        if isinstance(metric, dict):
            self.metric = pd.Series(metric)
        elif isinstance(metric, pd.Series):
            self.metric = metric
        else:
            raise ValueError(f"metric must be dict or pd.Series")

    def sum(self):
        return self.metric.sum()

    def mean(self):
        return self.metric.mean()

    def count(self):
        return self.metric.count()

    def abs(self):
        return self.__class__(self.metric.abs())

    @property
    def empty(self):
        return self.metric.empty

    @property

View on GitHub (pinned to 79633dd950)

Solutions

1. Pass the metric as a dict or a pd.Series; other types are not accepted.
2. Convert your metric data with pd.Series(...) or dict(...) before passing it.

When it happens

Trigger: This error is raised at qlib/backtest/high_performance_ds.py:517 when the guard condition fails: "metric must be dict or pd.Series". It triggers when the code path receives input or a state that violates the precondition checked at this point — e.g. an unimplemented abstract method being called, an unsupported argument type/value, or an invalid configuration. To avoid it, satisfy the documented precondition before this call: implement the required method in your subclass, or pass a supported value of the expected type as described by the message.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/qlib@79633dd950 (2026-08-15). Data as JSON: /api/errors/a5314721d288bd72. Report an issue: GitHub.