Importing text file with length delimiter

I have a text file, which contains only numbers.

For example:

2001 31110
199910 311

Its layout can be explained as follows:

1~4th numbers : Year
5~6th numbers : Month
7~8th numbers : Day
9th number : Sex
10th number : Married

However, I can't decide how to import this file into Stata.

For instance, if I use the command:

import delimited input.txt, delimiter(??)

What should I write in delimiter?

I don't necessarily need to use the above. I just want to import the data using whatever method.

Solution

The answer depends on what you want to do with the data later.

My understanding is that the spaces indicate a single digit for date-related numbers and that in the text file, only month or day can be single digit but not both. In addition, sex and married are binary indicators taking values 0 and 1.

Assuming the above are correct and the data below are included in a file data.txt:

Here's one way to do it:

clear 
import delimited data.txt, delimiter(" ") stringcols(_all)  

list

     +--------------------+
     |         v1      v2 |
     |--------------------|
  1. |       2001   31110 |
  2. |     199910     311 |
  3. |       1983   41201 |
  4. | 2012121500         |
     +--------------------+

replace v2 = "0" + v2 if v2 != ""
generate v3 = v1 + v2

generate year = substr(v3, 1, 4)
generate month = substr(v3, 5, 2)
generate day = substr(v3, 7, 2)

generate date = substr(v3, 1, 8)

generate sex = substr(v3, 9, 1)
generate married = substr(v3, 10, 1)

list
     +----------------------------------------------------------------------------------+
     |         v1       v2           v3   year   month   day       date   sex   married |
     |----------------------------------------------------------------------------------|
  1. |       2001   031110   2001031110   2001      03    11   20010311     1         0 |
  2. |     199910     0311   1999100311   1999      10    03   19991003     1         1 |
  3. |       1983   041201   1983041201   1983      04    12   19830412     0         1 |
  4. | 2012121500            2012121500   2012      12    15   20121215     0         0 |
     +----------------------------------------------------------------------------------+

You basically import everything in a maximum of two string variables, with a single space " " acting as a separator. The single-digit months or days are changed to two digits by adding a 0 at the front. Then, after you extract the relevant parts of the strings using the substr() function, you can simply convert the resulting variables to numeric as needed.

For example:

destring year month day sex married, replace

generate date2 = daily(date, "YMD")
format date2 %tdDD-NN-CCYY

. list date2 

     +------------+
     |      date2 |
     |------------|
  1. | 11-03-2001 |
  2. | 03-10-1999 |
  3. | 12-04-1983 |
  4. | 15-12-2012 |
     +------------+

If in your text file both month and day contain single digits, you follow the same logic as above but you will need to deal with a third variable as well after you import the data.