datetime

问题 I have a data set with a character column for months ( MONTH ) and a numeric column indicating years ( YEAR ). In order to work with it as panel data, I need to unite these YEAR and MONTH into a variable with a date format. I have tried to change the variable MONTH to numeric format and then to merge MONTH with the column YEAR . R would not recognize it as a date variable. It currently looks like this: STATE MONTH YEAR VALUE California JAN 2018 800 California FEB 2018 780 California MAR 2018

问题 In my application, the date and time need to be changed frequently when the tester tests the application. Currently, we have to use the system command date-s to change the system time，But this will cause other applications on the server to be affected as well。I want to change the Date() only this application, and I don't want to change the application itself, because there are so many places where new Date is used 回答1: The java.util.Date API is very very old. It was replaced by the Calendar

问题 I write these in Linux bash date -d "2018-08-21 02:00:00" +'%y-%m-%d %T' and it prints 2018-08-21 02:00:00 But when I write these date -d "2018-08-21 02:00:00 +1 hour" +'%y-%m-%d %T' it prints 2018-08-21 07:30:00 instead of 2018-08-21 03:00:00 It adds my timezone to the date . How can I ignore timezone when I'm adding time units? 回答1: What is happening is that the +1 is interpreted as the timezone UTC+1h . So it will convert your input date from UTC+1 to your local time-zone and then still

问题 Following Eric Lippert's post years back on precision of DateTime , I ran his test on .netcore and .NET Framework 4.5.2, on the same machine with Windows 10. var n = 1000; int i = 0; long[] diffs = new long[n]; while (i++ < n-1) { if (ticks != DateTime.Now.Ticks) { var newTicks = DateTime.UtcNow.Ticks; var diff = newTicks - ticks; diffs[i] = diff; ticks = newTicks; } } foreach (var d in diffs) { if (d == 0) Console.WriteLine("same"); else Console.WriteLine(d); } The result on .NET framework 4

问题 Following Eric Lippert's post years back on precision of DateTime , I ran his test on .netcore and .NET Framework 4.5.2, on the same machine with Windows 10. var n = 1000; int i = 0; long[] diffs = new long[n]; while (i++ < n-1) { if (ticks != DateTime.Now.Ticks) { var newTicks = DateTime.UtcNow.Ticks; var diff = newTicks - ticks; diffs[i] = diff; ticks = newTicks; } } foreach (var d in diffs) { if (d == 0) Console.WriteLine("same"); else Console.WriteLine(d); } The result on .NET framework 4

问题 I have two datetime (Timestamp) formatted columns in my dataframe, df['start'], df['end'] . I'd like to get the duration between the two dates. So I create the duration column df['duration'] = df['start'] - df['end'] However, now the duration column is formatted as numpy.timedelta64 , instead of datetime.timedelta as I would expect. >>> df['duration'][0] >>> numpy.timedelta64(0,'ns') While >>> df['start'][0] - df['end'][0] >>> datetime.timedelta(0) Can someone explain to me why the array

问题 I have two datetime (Timestamp) formatted columns in my dataframe, df['start'], df['end'] . I'd like to get the duration between the two dates. So I create the duration column df['duration'] = df['start'] - df['end'] However, now the duration column is formatted as numpy.timedelta64 , instead of datetime.timedelta as I would expect. >>> df['duration'][0] >>> numpy.timedelta64(0,'ns') While >>> df['start'][0] - df['end'][0] >>> datetime.timedelta(0) Can someone explain to me why the array

问题 I have two datetime (Timestamp) formatted columns in my dataframe, df['start'], df['end'] . I'd like to get the duration between the two dates. So I create the duration column df['duration'] = df['start'] - df['end'] However, now the duration column is formatted as numpy.timedelta64 , instead of datetime.timedelta as I would expect. >>> df['duration'][0] >>> numpy.timedelta64(0,'ns') While >>> df['start'][0] - df['end'][0] >>> datetime.timedelta(0) Can someone explain to me why the array

问题 I have two datetime (Timestamp) formatted columns in my dataframe, df['start'], df['end'] . I'd like to get the duration between the two dates. So I create the duration column df['duration'] = df['start'] - df['end'] However, now the duration column is formatted as numpy.timedelta64 , instead of datetime.timedelta as I would expect. >>> df['duration'][0] >>> numpy.timedelta64(0,'ns') While >>> df['start'][0] - df['end'][0] >>> datetime.timedelta(0) Can someone explain to me why the array

问题 I am trying to plot my data in the csv file. Currently my dates are not shown properly in the plot also if i am converting it. How can I change it to show the proper dat format as defined Y-m-d? The second question is that I am currently plotting all the dat in one plot but want to have for every Valuegroup one subplot. My code looks like the following: import pandas as pd import matplotlib.pyplot as plt csv_loader = pd.read_csv('C:/Test.csv', encoding='cp1252', sep=';', index_col=0).dropna()