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Map is one operation pandas does nicely that most other “wrap a fast language” dataframe tools do poorly. When it feels like you’re writing some external udf t
by data-ottawa 9mo ago
Map is one operation pandas does nicely that most other “wrap a fast language” dataframe tools do poorly.
When it feels like you’re writing some external udf thats executed in another environment, it does not feel as nice as throwing in a lambda, even if the lambda is not ideal.
- vegabook 9mo agoyou have map_elements in polars which does exactly this. https://docs.pola.rs/api/python/dev/reference/expressions/api/polars.Expr.map_elements.html https://docs.pola.rs/api/python/dev/reference/expressions/ap... You can also iter_rows into a lambda if you really want to. https://docs.pola.rs/api/python/stable/reference/dataframe/api/polars.DataFrame.iter_rows.html https://docs.pola.rs/api/python/stable/reference/dataframe/a... Personally I find it extremely rare that I need to do this given Polars expressions are so comprehensive, including when.then.otherwise when all else fails.
- data-ottawa 9mo agoThat one has a bit more friction than pandas because the return schema requirement -- pandas let's you get away with this bad practice. It also does batches when you declare scalar outputs, but you can't control the batch size, which usually isn't an issue, but I've run into situations where it is.
- deleted 9mo ago[deleted]