Shorter values and match

[Cristiano Bellavitis]

Good morning everyone,

I would kindly ask for help on two related matters.

First, I have a date variable that looks like this: 2021-08-27 14:31:47. I'd like to split it in date (2021-08-27) and time (14:31:47), basically creating two separate variables.

Second, I have a separate dataset with values associated with each date, and I would like to match them by Date. Below a summary of my two dataset and what I'd like to obtain after matching by Date. I'd like to bring the values of Dataset B into a new variable in Dataset A.

Thank you in advance,

Cristiano

Dataset A
Date
2021-08-27
2021-08-27
2021-08-27
2021-08-28
2021-08-29
2021-08-30

Dataset B
Date Value to match
2021-08-27 100
2021-08-28 110
2021-08-29 115
2021-08-30 95

Match (desired)
Date Value
2021-08-27 100
2021-08-27 100
2021-08-27 100
2021-08-28 110
2021-08-29 115
2021-08-30 95

[Nick Cox]

Please

use dataex to make it clear whether your date variables are strings or numeric with date formats

include an example of a date-time variable such as you describe but do not exemplify

[Cristiano Bellavitis]

Hi Nick,
this is the date variable. Basically I'd like to keep the empty values as empty, and create two vars with date and time.

* Example generated by -dataex-. For more info, type help dataex
clear
input str26 created_date                    
""                                                                          
""                          
"2021-08-27 14:31:47"       
"2022-01-11 20:04:50.105462"
end

The dataset B will have the date formatted properly (e.g. 2021-08-27) and will have another column with the numeric values I want to bring onto the other table (e.g. 100.15).

Thank you,

Cristiano

[Nick Cox]

Your daily date numeric variable is just

gen ddate = daily(word(created_date, 1), "YMD")

[Cristiano Bellavitis]

Thank you, Nick. The code works.

Would you happen to know how to match with the other dataset?

[Nick Cox]

I imagine that you mean to merge the datasets on daily date.

[Cristiano Bellavitis]

I think I found the solution, thank you.