[Python] What is the most efficient way to check if a Polars LazyFrame has duplicates?

With the help of claude sonnet 4, I cooked up this function, which I hope does what I asked it to do.

def has_duplicates_early_exit(df: pl.LazyFrame, subset: list[str]) -> bool:
"""Can exit early when first duplicate is found"""
return df.select(
pl.struct(subset).is_duplicated().any()
).collect().item()


Is this the most efficient you can do?

Continue reading...