Question

我的datetime列的日期框架格式为yyyy-mm-dd。

我想以整数格式yyyymmdd。我一直在使用这个

抛出错误

x=dates.apply(dt.datetime.strftime('%Y%m%d')).astype(int)

TypeError: descriptor 'strftime' requires a 'datetime.date' object but received a 'str'

这不起作用，因为我试图传递一个数组。我知道如果我只传递元素它会转换，但我怎么做更pythonic？我确实尝试过使用lambda，但这也没有用。

Answer 1

如果您的列是字符串，则需要先使用`pd.to_datetime'，

df['Date'] = pd.to_datetime(df['Date'])

然后，将.dt日期时间访问者与strftime：

一起使用

df = pd.DataFrame({'Date':pd.date_range('2017-01-01', periods = 60, freq='D')})

df.Date.dt.strftime('%Y%m%d').astype(int)

或者使用lambda函数：

df.Date.apply(lambda x: x.strftime('%Y%m%d')).astype(int)

输出：

0     20170101
1     20170102
2     20170103
3     20170104
4     20170105
5     20170106
6     20170107
7     20170108
8     20170109
9     20170110
10    20170111
11    20170112
12    20170113
13    20170114
14    20170115
15    20170116
16    20170117
17    20170118
18    20170119
19    20170120
20    20170121
21    20170122
22    20170123
23    20170124
24    20170125
25    20170126
26    20170127
27    20170128
28    20170129
29    20170130
30    20170131
31    20170201
32    20170202
33    20170203
34    20170204
35    20170205
36    20170206
37    20170207
38    20170208
39    20170209
40    20170210
41    20170211
42    20170212
43    20170213
44    20170214
45    20170215
46    20170216
47    20170217
48    20170218
49    20170219
50    20170220
51    20170221
52    20170222
53    20170223
54    20170224
55    20170225
56    20170226
57    20170227
58    20170228
59    20170301
Name: Date, dtype: int32

Answer 2

你知道吗？我有一个肮脏的方式

df.Date.dt.year*10000+df.Date.dt.month*100+df.Date.dt.day
Out[498]: 
0     20170101
1     20170102
2     20170103
3     20170104
4     20170105
5     20170106
6     20170107
7     20170108
8     20170109
9     20170110
10    20170111
11    20170112
12    20170113
13    20170114
14    20170115
15    20170116
16    20170117
17    20170118
18    20170119
19    20170120
20    20170121
21    20170122
22    20170123
23    20170124
24    20170125
25    20170126
26    20170127
27    20170128
28    20170129
29    20170130
30    20170131
31    20170201
32    20170202
33    20170203
34    20170204
35    20170205
36    20170206
37    20170207
38    20170208
39    20170209
40    20170210
41    20170211
42    20170212
43    20170213
44    20170214
45    20170215
46    20170216
47    20170217
48    20170218
49    20170219
50    20170220
51    20170221
52    20170222
53    20170223
54    20170224
55    20170225
56    20170226
57    20170227
58    20170228
59    20170301
Name: Date, dtype: int64

将pandas datetime列yyyy-mm-dd转换为YYYMMDD

2 个答案: