[英]Python - Retrieving last 30 days data from dataframe pandas
我有一個包含六個月錯誤日志的數據框,每天收集。 我想從最后一個日期檢索過去 30 天的記錄。 最后一次約會不是今天。
例如:我有五月、六月、七月和August 15
日之前的數據,我想檢索從August 15
到July 15
August 15
July 15
數據,使其成為 30 天的記錄。
有沒有辦法在 Python Pandas 中做到這一點?
這是示例數據框:
Error_Description Date Weekend Type
N17739 Limit switch X- 5/1/2015 5/3/2015 Critical
N17739 Limit switch Y- 5/1/2015 5/3/2015 Critical
N938 Key non-functional 5/1/2015 5/3/2015 Non-Critical
P124 Magazine is running 5/1/2015 5/3/2015 Non-Critical
N17738 Limit switch Z+ 5/1/2015 5/3/2015 Critical
N938 Key non-functional 5/1/2015 5/3/2015 Non-Critical
... ... ... ...
P873 ENCLOSURE DOOR 8/24/2015 8/30/2015 Non-Critical
N3065 Reset M114 8/24/2015 8/30/2015 Non-Critical
N3065 Reset M114, 8/24/2015 8/30/2015 Non-Critical
N2853 Synchronization 8/24/2015 8/30/2015 Critical
P152 ENCLOSURE 8/24/2015 8/30/2015 Non-Critical
N6236 has stopped 8/24/2015 8/30/2015 Critical
lastdayfrom
日期用於按功能loc選擇DataFrame
的最后30天。
lastdayfrom = pd.to_datetime('8/24/2015')
print lastdayfrom
#2015-08-24 00:00:00
print df
# Error_Description Date Weekend Type
#0 N17739 Limit switch X- 2015-05-01 2015-05-03 Critical
#1 N17739 Limit switch Y- 2015-05-01 2015-05-03 Critical
#2 N938 Key non-functional 2015-05-01 2015-05-03 Non-Critical
#3 P124 Magazine is running 2015-05-01 2015-05-03 Non-Critical
#4 N17738 Limit switch Z+ 2015-02-01 2015-05-03 Critical
#5 N938 Key non-functional 2015-07-25 2015-05-03 Non-Critical
#6 P873 ENCLOSURE DOOR 2015-07-24 2015-08-30 Non-Critical
#7 N3065 Reset M114 2015-07-21 2015-08-21 Non-Critical
#8 N3065 Reset M114, 2015-08-22 2015-08-22 Non-Critical
#9 N2853 Synchronization 2015-08-23 2015-08-30 Critical
#10 P152 ENCLOSURE 2015-08-24 2015-08-30 Non-Critical
#11 N6236 has stopped 2015-08-24 2015-08-30 Critical
print df.dtypes
#Error_Description object
#Date datetime64[ns]
#Weekend datetime64[ns]
#Type object
#dtype: object
#set index from column Date
df = df.set_index('Date')
#if datetimeindex isn't order, order it
df= df.sort_index()
#last 30 days of date lastday
df = df.loc[lastdayfrom - pd.Timedelta(days=30):lastdayfrom].reset_index()
print df
# Date Error_Description Weekend Type
#0 2015-07-25 N3065 Reset M114 2015-08-21 Non-Critical
#1 2015-08-22 N3065 Reset M114, 2015-08-22 Non-Critical
#2 2015-08-23 N2853 Synchronization 2015-08-30 Critical
#3 2015-08-24 P152 ENCLOSURE 2015-08-30 Non-Critical
#4 2015-08-24 N6236 has stopped 2015-08-30 Critical
您可以使用DataFrame.last_valid_index()
查找最后一行的標簽,然后減去DateOffset(30, 'D')
以返回30天:
df[df.last_valid_index()-pandas.DateOffset(30, 'D'):]
其他兩個答案(當前)假設日期是索引,但至少在 python3 中,您可以通過簡單的掩碼來解決這個問題( .query(..)
不起作用)。
df[df["Date"] >= (pd.to_datetime('8/24/2015') - pd.Timedelta(days=30))]
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