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[英]how to convert multiple columns of pandas dataframe with object/categorical datatype to int64 in python?
[英]Python: convert series object columns in pandas dataframe to int64 dtype
我有以下數據框:
Day_Part Start_Time End_Time
Breakfast 9:00 11:00
Lunch 12:00 14:00
Dinner 19:00 23:00
Start_Time和End_time列現在是“系列對象”。 我想將這些列中的值轉換為int64 dtype。
這就是我希望數據框看起來像的樣子:
Day_Part Start_Time End_Time
Breakfast 9 11
Lunch 12 14
Dinner 19 23
*任何幫助是極大的贊賞。
您可以先轉換為to_timedelta
,然后提取hour
:
df['Start_Time'] = pd.to_timedelta(df['Start_Time']+ ':00').dt.components.hours
df['End_Time'] = pd.to_timedelta(df['End_Time']+ ':00').dt.components.hours
print (df)
Day_Part Start_Time End_Time
0 Breakfast 9 11
1 Lunch 12 14
2 Dinner 19 23
使用split
並強制轉換為int
另一個解決方案:
df['Start_Time'] = df['Start_Time'].str.split(':').str[0].astype(int)
df['End_Time'] = df['End_Time'].str.split(':').str[0].astype(int)
print (df)
Day_Part Start_Time End_Time
0 Breakfast 9 11
1 Lunch 12 14
2 Dinner 19 23
用解法extract
並轉換為int
:
df['Start_Time'] = df['Start_Time'].str.extract('(\d*):', expand=False).astype(int)
df['End_Time'] = df['End_Time'].str.extract('(\d*):', expand=False).astype(int)
print (df)
Day_Part Start_Time End_Time
0 Breakfast 9 11
1 Lunch 12 14
2 Dinner 19 23
轉換為to_datetime
解決方案:
df['Start_Time'] = pd.to_datetime(df['Start_Time'], format='%H:%M').dt.hour
df['End_Time'] = pd.to_datetime(df['End_Time'], format='%H:%M').dt.hour
print (df)
Day_Part Start_Time End_Time
0 Breakfast 9 11
1 Lunch 12 14
2 Dinner 19 23
時間 :
#[300000 rows x 3 columns]
df = pd.concat([df]*100000).reset_index(drop=True)
print (df)
In [158]: %timeit pd.to_timedelta(df['Start_Time']+ ':00').dt.components.hours
1 loop, best of 3: 7.12 s per loop
In [159]: %timeit df['Start_Time'].str.split(':').str[0].astype(int)
1 loop, best of 3: 415 ms per loop
In [160]: %timeit df['Start_Time'].str.extract('(\d*):', expand=False).astype(int)
1 loop, best of 3: 654 ms per loop
In [166]: %timeit pd.to_datetime(df['Start_Time'], format='%H:%M').dt.hour
1 loop, best of 3: 1.26 s per loop
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