Variables not related to series

[Daniel Morales]

Hi, there is a way to declare and use variables not related to a field o series, I mean, could I do create variables like this

declare var as integer or something like that?

because generate or egen make series.

[George Ford]

I don't get it. Maybe post some data using dataex and state what you need more specifically.

[Daniel Morales]

how do I create free variables? since generate or egen create series, how can I create free variables?

[William Lisowski]

Hi, there is a way to declare and use variables not related to a field o series

I do not know what you mean by "a field o series", nor what you intend in post #3 by "free variables". Do you perhaps want to create variables that do not persist within your dataset after the execution of your do-file or program?

. sysuse auto, clear
(1978 automobile data)

. keep make price

. ds
make   price

. tempvar gnxl

. generate `gnxl' = 42

. replace `gnxl' = `gnxl'+_n
(74 real changes made)

. list in 1/5

     +----------------------------------+
     | make            price   __000001 |
     |----------------------------------|
  1. | AMC Concord     4,099         43 |
  2. | AMC Pacer       4,749         44 |
  3. | AMC Spirit      3,799         45 |
  4. | Buick Century   4,816         46 |
  5. | Buick Electra   7,827         47 |
     +----------------------------------+

. 
end of do-file

. ds
make   price

. list in 1/5

     +-----------------------+
     | make            price |
     |-----------------------|
  1. | AMC Concord     4,099 |
  2. | AMC Pacer       4,749 |
  3. | AMC Spirit      3,799 |
  4. | Buick Century   4,816 |
  5. | Buick Electra   7,827 |
     +-----------------------+

.

[Nick Cox]

I think Daniel may have in mind that in many languages variables can be scalars, and indeed in Mata too an assignment such as

answer = 42 

is perfectly fine. In Stata itself, you can hold text or numeric constants in macros or scalars. A good overview is given in

https://www.stata.com/manuals/u18.pdf

Occasionally it is a good idea to put a constant into a Stata variable:

gen answer = 42

but usually that is a waste of memory.

[Daniel Morales]

thank you Mr. Cox.