2023-01-29-medium-unroll-config.py

from convtools import conversion as c


config = {
    "key1": "external key1",
    "key2": "external key2",
    "key3": "external key3",
}


def f_base(data):
    return [
        {key: item[key_external] for key, key_external in config.items()}
        for item in data
    ]


f_convtools = c.list_comp(
    {key: c.item(key_external) for key, key_external in config.items()}
).gen_converter()


data = [{"external key1": 1, "external key2": 2, "external key3": 3}] * 10000

assert f_base(data) == f_convtools(data)

"""
In [36]: %timeit f_base(data)
2.66 ms ± 6.67 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)

In [37]: %timeit f_convtools(data)
1.29 ms ± 3.83 µs per loop (mean ± std. dev. of 7 runs, 1,000 loops each)

CODE-GEN PHASE TAKES REASONABLE TIME (and the converter function can be reused):
In [40]: %%timeit
    ...: f_convtools = c.list_comp(
    ...:     {key: c.item(key_external) for key, key_external in config.items()}
    ...: ).gen_converter()
    ...:
    ...:
62.4 µs ± 69.7 ns per loop (mean ± std. dev. of 7 runs, 10,000 loops each)
"""