I.e., vertically concatenates two datasets, appending the rows of the second to the end of the first.

When the two datasets contain different columns, the join parameter controls whether only the common columns are kept (inner), or all columns (outer). In the latter case, rows will have missing values (NaNs), where a column only existed in one of the two datasets.

join
string
default: "outer"required

Whether to do concatenate using an “inner” or “outer” join of columns. When "inner", only common columns will be kept. When "outer", all columns will be kept.

Values must be one of the following:

  • inner
  • outer