Truncating long variable names

[Sonnen Blume]

Hi,
Some of the variables in my dataset are too long, and trying to rename them returns an error message. Is there any trick to get around this error?

............invalid name
r(198);

[William Lisowski]

What do you mean by "are too long"? Do you mean you have a variable name in your dataset that exceeds Stata's built-in (and apparently unchangeable) limit of 32 characters? Or do you mean they are longer than you would like them to be? If they exceed the 32 character limit, how were they created?

What was the precise command you issued that resulted in the error message you display in post #1?

You apparently imagine that among the members of Statalist there will be at least one who reads your post and has experienced the problem you describe and can answer your question directly. That's a fairly limited pool of potential answerers, and you can expand that pool by providing an adequate description of your problem so that those who have not experienced it but are intrigued by the possibility can fully understand the problem and attempt to deduce a solution.

[Sonnen Blume]

What do you mean by "are too long"? Do you mean you have a variable name in your dataset that exceeds Stata's built-in (and apparently unchangeable) limit of 32 characters? Or do you mean they are longer than you would like them to be? If they exceed the 32 character limit, how were they created?

What was the precise command you issued that resulted in the error message you display in post #1?

You apparently imagine that among the members of Statalist there will be at least one who reads your post and has experienced the problem you describe and can answer your question directly. That's a fairly limited pool of potential answerers, and you can expand that pool by providing an adequate description of your problem so that those who have not experienced it but are intrigued by the possibility can fully understand the problem and attempt to deduce a solution.

Hi William,
The data were prepared outside Stata. Here is the original command:

. rename MessageTraditionalMediaUnderstand  Item4
MessageTraditionalMediaUnderstand invalid name
r(198);

[William Lisowski]

To start with, you should tell whomever prepared the Stata dataset that they limit the variable names to 32 characters in the future.

Secondly, I was able to devise a technique to work around this problem.

. describe, fullnames

Contains data from /Users/lisowskiw/Downloads/long.dta
  obs:             1                          
 vars:             2                          27 Apr 2020 16:33
------------------------------------------------------------------------------------------------
              storage   display    value
variable name   type    format     label      variable label
------------------------------------------------------------------------------------------------
id              float   %9.0g                 
MessageTraditionalMediaUnderstand@���
                float   %9.0g                 
------------------------------------------------------------------------------------------------
Sorted by: 
     Note: Dataset has changed since last saved.

. mata: st_varrename(2,"something_else")

. describe, fullnames

Contains data from /Users/lisowskiw/Downloads/long.dta
  obs:             1                          
 vars:             2                          27 Apr 2020 16:33
------------------------------------------------------------------------------------------------
              storage   display    value
variable name   type    format     label      variable label
------------------------------------------------------------------------------------------------
id              float   %9.0g                 
something_else  float   %9.0g                 
------------------------------------------------------------------------------------------------
Sorted by: 
     Note: Dataset has changed since last saved.

The first argument to st_varrename() tells it to rename the second variable in the dataset - in this case, the one with the long name.

[Sonnen Blume]

Thanks so much William. This is really clever. Is it possible to rename several variables at the same time using this technique? I tried:

 
  mata: st_varrename((2,5), "something_else" "something_else1")

but it didn't work.

[William Lisowski]

The output of help st_varrename() suggests not.

[daniel klein]

Well, that is easy to program both in Stata and Mata. Here is a draft for Stata

local varindex 2 5
local varnames "somehting_else" "something_else1"

local i 0
foreach idx of local varindex {
    local name : word `++i' of `varnames'
    mata : st_varrename(`idx', "`name'")
}

If you literally wanted the new names to be a common name with a running number added, then

local varindex 2 5

local i 0
foreach idx of local varindex {
    mata : st_varrename(`idx', "something_else`++i'")
}

btw. StataCorp had a non-documented renamevarno that could be used if it is still around in Stata 16

local varindex 2 5

local i 0
foreach idx of local varindex {
    varrenameno `idx'  something_else`++i'
}

You could shift the original name into the variable label or characteristics if you wanted to keep them. You did no ask for this, so I will stop here.

Best
Daniel

[Sonnen Blume]

Thanks a lot Daniel! This is very helpful.