Open
Description
Pandas version checks
- I have checked that the issue still exists on the latest versions of the docs on
mainhere
Location of the documentation
https://pandas.pydata.org/docs/reference/api/pandas.merge_asof.html
Documentation problem
For each row in the left DataFrame:
A “backward” search selects the last row in the right DataFrame whose ‘on’ key is less than or equal to the left’s key.
This is incorrect, as evidenced here:
left = pd.DataFrame(
{
"id": ["a"],
"date": pd.to_datetime(
["20080102"]
),
},
)
right = pd.DataFrame(
{
"id": ["a"],
"date": pd.to_datetime([
"20080101",
])
},
)
pd.merge_asof(left=left, right=right, by="id", on="date")
| id | date | |
|---|---|---|
| a | 2008-01-02 |
Suggested fix for documentation
For each row in the left DataFrame:
A “backward” search selects the last row in the **left** DataFrame whose ‘on’ key is less than or equal to the left’s key.