Creating a string variable with multiple different word values

[Ethan Medlin]

Hello,

I am relatively new to STATA, with only a couple months experience and not much string experience.

I want to create a variable that stores 10 separate different words.

Ex:
animal:
cat
dog
lizard
bird
etc

I tried doing something like
gen animal = "cat" + " " + "dog"....

but that just gave me:

animal = cat dog lizard bird

and the results aren't all split up. I am doing this so that I can basically use this string value as the qualifier for an f statement that will do a command when the string is equal to one of the word values.

Thanks!

[Joseph Coveney]

With an empty dataset, you could

input str250 animal
cat
dog
lizard
bird
etc
end

The string length is set arbitrarily large in order to accommodate any lengthy animal names. (Afterward, you can use compress if memory is at a premium.) If any of your animals above had spaces, you'd need to surround it by double-quotation marks.

With this dataset of animals, you could merge or cross (or other command of this nature) with another dataset on which you want to use the if statement or command qualifier.

[Marcos Almeida]

Please read the FAQ. There you'll find the best approach to share data/output/command.

This is the best way to entail an insightful reply.

[David Benson]

* Example generated by -dataex-. To install: ssc install dataex
clear
input str10 animal float is_mammal
"cat"        1
"dog"        1
"lizard"     0
"bird"       0
"lion"       1
"tiger"      1
"bear"       1
"Black bear" 1
"Brown Bear" 0
end

So, once you get the string data entered that you need, this is how you can do a command (in this case, set variable is_mammal==1) when the string is equal to one of the word values.

gen is_mammal = 0
replace is_mammal = 1 if strpos(animal, "cat") > 0

* If you have many, you might want to do a loop:
foreach name in "dog" "bear" "deer" "lion" "tiger" {
replace is_mammal = 1 if strpos(animal, "`name'") > 0
}

. list animal is_mammal

     +-----------------------+
     |     animal   is_mam~l |
     |-----------------------|
  1. |        cat          1 |
  2. |        dog          1 |
  3. |     lizard          0 |
  4. |       bird          0 |
  5. |       lion          1 |
     |-----------------------|
  6. |      tiger          1 |
  7. |       bear          1 |
  8. | Black bear          1 |
  9. | Brown Bear          0 |
     +-----------------------+

Note that the string function strpos is case sensitive, so strpos(animal, "bear") matched to "bear" and "Black bear" but not "Brown Bear". Use the string function strupper() to convert everything to upper case if matching on case is an issue.

[Nick Cox]

I read #1 differently from some previous answers. I interpret your goal -- slight editing here -- as

I want to use this string value as the qualifier for an if statement that will do a command when a string variable is equal to one of the word values

You can always go

... if animal == "cat"

and there is no obvious need for or value in putting "cat" in a variable with other possibilities.