Does loc in pandas use vectorised logic or a for loop?

问题

I access rows in pandas with the loc function as below:

pdf.loc[pdf.a>2]

Is this vectorised? Is it better than using numpy

pdf[pdf.a>2]

回答1:

This timing suggests there is no slow down with loc

testa = pd.DataFrame(np.arange(10000000),columns =['q'])
%timeit testb = testa.loc[testa.q>6] 
%timeit testc = testa[testa.q>7]

1 loop, best of 3: 207 ms per loop
1 loop, best of 3: 208 ms per loop

来源：https://stackoverflow.com/questions/55874138/does-loc-in-pandas-use-vectorised-logic-or-a-for-loop