It is not. df = pd.DataFrame({"foo": np.random.randn(100000)}) pandas map: df["foo"].map(

It is not. df = pd.DataFrame({"foo": np.random.randn(100000)}) pandas map: df["foo"].map(lambda x: x * 2) 18.1 ms ± 109 µs per loop (mean ± std. dev. of 7 runs, 100 loops each) pandas apply: df["foo"].apply(lambda x: x * 2) 17.9 ms ± 46.6 µs per loop (mean ± std. dev. of 7 runs, 100 loops each) Vectorised function, using underlying numpy operations: df["foo"] * 2 267 µs ± 11.8 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)