Python 熊猫：选择具有特定月份和日期的所有日期
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Pandas: select all dates with specific month and day
提问by user3439329
I have a dataframe full of dates and I would like to select all dates where the month==12 and the day==25 and add replace the zero in the xmascolumn with a 1.
我有一个充满日期的数据框，我想选择月==12和日==25的所有日期，并添加用xmas1替换列中的零。
Anyway to do this? the second line of my code errors out.
无论如何要做到这一点？我的代码的第二行出错了。
df = DataFrame({'date':[datetime(2013,1,1).date() + timedelta(days=i) for i in range(0,365*2)], 'xmas':np.zeros(365*2)})
df[df['date'].month==12 and df['date'].day==25] = 1
回答by EdChum
Basically what you tried won't work as you need to use the &to compare arrays, additionally you need to use parentheses due to operator precedence. On top of this you should use locto perform the indexing:
基本上您尝试的方法不起作用，因为您需要使用&来比较数组，此外，由于运算符优先级，您还需要使用括号。最重要的是，您应该使用它loc来执行索引：
df.loc[(df['date'].month==12) & (df['date'].day==25), 'xmas'] = 1
回答by Shayan RC
Pandas Serieswith datetime now behaves differently. See .dt accessor.
Series带有日期时间的Pandas现在表现不同。请参阅.dt 访问器。
This is how it should be done now:
现在应该这样做：
df.loc[(df['date'].dt.day==25) & (cust_df['date'].dt.month==12), 'xmas'] = 1
