Pandas Dataframe，为星期几赋值。特征提取

Question

我正在提取特征以查找工作日。我到目前为止是这样的：

days = {0:'Mon', 1: 'Tues', 2:'Wed', 3:'Thurs', 4:'Fri', 5:'Sat', 6:'Sun'}
data['day_of_week'] = data['day_of_week'].apply(lambda x: days[x])
data['if_Weekday'] = np.where( (data['day_of_week'] == 'Mon') | (data['day_of_week'] == 'Tues') | (data['day_of_week'] == 'Wed') | (data['day_of_week'] == 'Thurs') | (data['day_of_week'] == 'Friday'), '1', '0')

此代码会将周一至周五指定为 1，将周六至周日指定为 0。但是，我想为工作日分配不同的值。例如，Mon = 1，Tues = 2，Wed = 3，Thurs = 4，Fri = 5，Sat 和 Sun 都应该等于 0。

如有任何帮助，我们将不胜感激。

Answer 1

OK 我认为这里最简单的事情是使用 np.where 来测试工作日是否大于或等于 5 如果是则分配 0，否则 return 工作日值并向其添加 1：

In [21]:
df['is_weekday'] = np.where(df['weekday'] >= 5, 0, df['weekday'] + 1)
df
Out[21]:
       dates  weekday  is_weekday
0 2016-01-01        4           5
1 2016-01-02        5           0
2 2016-01-03        6           0
3 2016-01-04        0           1
4 2016-01-05        1           2
5 2016-01-06        2           3
6 2016-01-07        3           4
7 2016-01-08        4           5
8 2016-01-09        5           0
9 2016-01-10        6           0

Answer 2

我想你可以使用 mask:

data = pd.DataFrame({'day_of_week':[0,1,2,3,4,5,6]})

#original column to new, add 1
data['if_Weekday'] = data['day_of_week'] + 1

#map days if necessary
days = {0:'Mon', 1: 'Tues', 2:'Wed', 3:'Thurs', 4:'Fri', 5:'Sat', 6:'Sun'}
data['day_of_week'] = data['day_of_week'].map(days)

#correct weekend days
data['if_Weekday'] = data['if_Weekday'].mask(data['if_Weekday'] >= 6, 0)

print (data)
  day_of_week  if_Weekday
0         Mon           1
1        Tues           2
2         Wed           3
3       Thurs           4
4         Fri           5
5         Sat           0
6         Sun           0

Pandas Dataframe，为星期几赋值。特征提取

Pandas Dataframe, assign values to day of the week. Feature extraction

python

pandas

numpy

multiple-columns

dayofweek