python-2.7 - pandas:根据第一个字符映射新值

Question

有没有办法根据当前值的第一个字符将新值映射到数据框列。

我当前的代码:

ncesvars['urbantype'] = np.where(ncesvars['urbantype'].str.startswith('1'), 'city', ncesvars['urbantype'])
ncesvars['urbantype'] = np.where(ncesvars['urbantype'].str.startswith('2'), 'suburban', ncesvars['urbantype'])
ncesvars['urbantype'] = np.where(ncesvars['urbantype'].str.startswith('3'), 'town', ncesvars['urbantype'])
ncesvars['urbantype'] = np.where(ncesvars['urbantype'].str.startswith('4'), 'rural', ncesvars['urbantype'])

我正在考虑使用某种dict，然后使用pd.replace，但不确定如何使用.str.startswith( )

Answer 1

尝试类似的操作:

ncesvars['urbantype'] = ncesvars['urbantype'].replace({
    r'^1.*', 'city', 
    r'^2.*', 'suburban'},
    regex=True)

测试:

In [32]: w
Out[32]:
     word
0    1_A_
1  word03
2  word02
3  word00
4    2xxx
5  word04
6  word01
7  word02
8  word04
9    3aaa

In [33]: w['word'].replace({r'^1.*': 'city', r'^2.*': 'suburban', r'^3.*': 'town'}, regex=True)
Out[33]:
0        city
1      word03
2      word02
3      word00
4    suburban
5      word04
6      word01
7      word02
8      word04
9        town
Name: word, dtype: object