如何从SPSS中的DateTime中减去某些特定分数

Question

我在SPSS中导入的列中有时间戳。例如，7/6/2011 2:21在名为'Observation'的列中

这是字符串格式。现在我也有这些数据的时区更正。所以，-60意味着从这个日期减去60分钟。

我该如何在SPSS语法中执行此操作？

Answer 1

在SPSS中有本地日期格式，但不幸的是，它似乎没有包含您发布的示例。我会解析字符串字段的开头，以获得mm/dd/yyyy和hh:mm部分，将其转换为其代表性时间格式，然后进行时间计算。

有关示例

data list fixed/observation (A25). 
begin data 
7/6/2011 2:21 
10/11/2011 15:42 
07/06/2011 02:21 
3/15/2011 0:21 
end data. 

*getting the data part, assuming the space will always delimit the two parts. 
compute #space = char.index(observation," "). 
string date (A10). 
compute date = char.substr(observation,1,#space-1). 
*getting the time part. 
string time (A5). 
compute time = char.substr(observation,#space+1,5). 
execute. 

*now converting them into date formats. 
alter type date (A10 = ADATE10). 
alter type time (A5 = TIME5). 
*you should check these carefully to make sure they were converted correctly. 
*now making one time variable. 
compute date_time = date + time. 
formats date_time (DATETIME17). 
execute. 

*now it is just as simple as subtracting the specified value. 
compute date_time_adj = DATESUM(date_time,-60,"minutes"). 
execute. 
formats date_time_adj (DATETIME17).