根据值的索引重新排序系列行

Question

我有一个大熊猫系列，所以优化是关键

pd.Series(['I like apples', 'They went skiing vacation', 'Apples are tasty', 'The skiing was great'], dtype='string')

0                I like apples
1    They went skiing vacation
2             Apples are tasty
3         The skiing was great
dtype: string

考虑行是字符串列表，即第 0 行是 ['I', 'like', 'apples']。

我想获取“apples”的索引并根据该索引的值对行重新排序。在这个例子中，系列看起来像：

2             Apples are tasty
0                I like apples
1    They went skiing vacation
3         The skiing was great
dtype: string

因为“apples”的索引（忽略区分大小写）在第 2 行中为 0。

Answer 1

使用Series.str.contains

#create DataFrame by split and reshape
s1 = s.str.split(expand=True).stack()
#filter only matched apple rows, sorting by second level (possition of apples)
idx  = s1[s1.str.contains('apples', case=False)].sort_index(level=1).index

#get original index by uion and select by loc for change ordering
s = s.loc[idx.remove_unused_levels().levels[0].union(s.index, sort=False)]
print (s)
2             Apples are tasty
0                I like apples
1    They went skiing vacation
3         The skiing was great
dtype: string

列表理解和枚举的另一个想法：

a = [next(iter(i for i, j in enumerate(x.split()) if j.lower() == 'apples'), len(s)*10) for x in s]
print (a)
[2, 40, 0, 40]

s = s.loc[np.array(a).argsort()]
print (s)
2             Apples are tasty
0                I like apples
1    They went skiing vacation
3         The skiing was great
dtype: string