以特定順序重復pandas Series

如果性能很重要，請將np.tile與Series.loc一起使用：

a = s.loc[np.tile(s.index, 2)]
print (a)
0    a
1    b
2    c
0    a
1    b
2    c
dtype: object

s = pd.Series(['a', 'b', 'c'])

In [25]: %timeit (s.loc[np.tile(s.index, 2000)])
612 μs ± 26.3 μs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

In [26]: %timeit (pd.concat([s] * 2000))
22.2 ms ± 251 μs per loop (mean ± std. dev. of 7 runs, 10 loops each)

EDIT:

s = pd.Series(['a', 'b', 'c'], index = pd.date_range('2015-01-01', periods=3))
print (s)

a = s.loc[np.tile(s.index, 2)]
print (a)
2015-01-01    a
2015-01-02    b
2015-01-03    c
2015-01-01    a
2015-01-02    b
2015-01-03    c
dtype: object