Polars - to_dicts(). Is the order of the List of Dictionaries guaranteed?

Question

I am leveraging the function .to_dicts() in my testing the resulting list of dictionaries has the same order as the dataframe.

df = pl.DataFrame(data={
    "name": ["Alice", "Bob", "Charlie"],
    "age": [30, 25, 35],
    "city": ["New York", "London", "Paris"],
}).sort(by=['name'], descending=True)

data = df.to_dicts()

for record in data:
    print(record)

Results in:

{'name': 'Charlie', 'age': 35, 'city': 'Paris'}
{'name': 'Bob', 'age': 25, 'city': 'London'}
{'name': 'Alice', 'age': 30, 'city': 'New York'}

Does anyone know if that is guaranteed to happen every time?

Answer 1

TLDR. Yes.

This can be seen by inspecting this underlying rust function, which maps over the indices of the DataFrame in order.