[Python] In Polars, how can I figure out which column each value returned by .min_horizontal()...

In python Polars, df.min_horizontal() returns a pl.Series with the minimum value of each row in the DataFrame.

How can I figure out which column each value in the Series originally came from?

For example, for:

df = pl.DataFrame({
"a": [1, 8, 3],
"b": [4, 5, 2],
"c": [7, 2, 9]
})
min_values = df.min_horizontal()


min_values will be a pl.Series [1,2,2].

I'd like to also get a series or column ['a', 'c', 'b'], which are the names of the columns the minimum values came from.

I can't come up with a solution that does not involve iterating row-wise or colum-wise over the whole DataFrame, but I feel like there must be a more elegant way.

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