Re: st: changing values of a string variable

[Nick Cox <njcoxstata@gmail.com>]

Prakash's opening statement is incorrect. If you -encode- a string
variable, it loses no property and indeed stays exactly as it is. What
happens is that a numeric variable is created with value labels equal
to the string values.

Tashi appears to be seeking something like the last line here

sysuse auto
label def rep78 1 appalling 2 adequate 3 average 4 amazing 5 astounding
label val rep78

. count if rep78=="average":rep78
   30

For more, see in [U] and e.g.

SJ-4-4  dm0009  . . . . . . .  Stata tip 14: Using value labels in expressions
        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  K. Higbee
        Q4/04   SJ 4(4):488--489                                 (no commands)
        tips for using value labels in expressions

Ken Higbee's paper is accessible at

http://www.stata-journal.com/sjpdf.html?articlenum=dm0009

This syntax has been in Stata a very long time. I don't use it, partly
because I keep forgetting about it and partly because I would need to
look it up to remember what it is, and my wild guess is that many
experienced users would say something similar.

Nick


Prakash Singh [edited slightly]

> when you -encode- any variable it loses its string property so
> there would be numeric value corresponding to id_131 in firms1 and you
> should use that value in your command line

tashi lama

>>  I found matters similar to what I am going to post have been been discussed in the past but I am not sure if I understood. Here is my dataset
>>
>> hits firms
>> 3     id_6429
>> 10    id_131
>> 8     id_2837
>>
>> 12    id_90

>> The problem is to have sth like this
>>
>> hits    firms
>>
>> 3     .
>>
>> 10    id_131
>> 8     .
>>
>> 12    .
>>
>>
>> so I said    1.  encode firm, gen(firm1)
>>
>>                 replace firm1=. if firm1!=id_131
>>
>>                 drop firms
>>
>>  I also tried   2.   replace firms="" if firms!="id_131"

>> It didn't give me the expected output although I feel like my codes are correct at least in principle. Any idea?

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