How to preserve extra spaces in a local?

[Harshita Joshi]

Hi everyone,

My question is about how to preserve extra spaces in a local. I have a local as follows:

local Lab ""Abc tests done on patients" "Abc  Pregnacy tests done""

(Note that the 2nd item in the local has extra spaces - I want to preserve these.)

However, the local seems to be saving this item without the extra spaces:

. macro list _Lab
_Lab:           "Abc tests done on patients" "Abc Pregnacy tests done"

This is an issue, as I later want to replace an observation if it's value is "Abc Pregnacy tests done" (the observation has a double space).

Does anyone know how I can preserve the double space in the local? Many thanks in advance!

[Clyde Schechter]

This is very odd. On the one hand I can reproduce your result. But, if I -display- the macro, or if I check the string length of the second word of `Lab', Stata does exhibit the presence of the extra blank space. This may be some peculiarity (bug?) in -macro list-.

. clear*

.
. local Lab ""Abc tests done on patients" "Abc  Pregnacy tests done""

.
. macro list _Lab // EXTRA BLANK IS MISSING
_Lab:           "Abc tests done on patients" "Abc Pregnacy tests done"

.
. display `"`Lab'"' // EXTRA BLANK IS NOT MISSING
"Abc tests done on patients" "Abc  Pregnacy tests done"

.
. display strlen("Abc  Pregnacy tests done")
24

.
. display strlen(`"`:word 2 of `Lab''"')
24

I would consider reporting this to Tech Support at StataCorp. I don't see anything in the help file or documentation that explains this behavior.

[daniel klein]

You should probably be using compound quotes, as in

local Lab `""Abc tests done on patients" "Abc  Pregnacy tests done""'

However even with compound quotes, I get

. macro list
[...]
_Lab:           "Abc tests done on patients" "Abc Pregnacy tests done"

This seems to be a glitch in macro list as I also get

. display `"`Lab'"'
"Abc tests done on patients" "Abc  Pregnacy tests done"

. mata : st_local("Lab")
  "Abc tests done on patients" "Abc  Pregnacy tests done"

I am using Stata 16.1, fully updated, on a Win 10 system.


EDIT: Clyde was quicker along the same path.

[Harshita Joshi]

Thanks so much, Clyde and Daniel!

I ultimately need to run a loop which goes through the strings in the local and replaces a variable if the variable matches the string in the local (simplified version of code below -

 local Lab ""Abc tests done on patients" "Abc  Pregnacy tests done"" local Other ""X" "Y"" local services Lab Other

    foreach ser of local services {
        forvalues n = 1/`number' {
            loc s: word `n' of ``ser''
            replace A="`ser'`n'" if A=="`s'"
            }    
        }

However, because the local wasn't preserving the extra space, the replacement wasn't happening when my variable A was = "Abc Pregnacy tests done" (with the extra space -- Edit: funnily enough even Statalist is removing the extra space!). I instead used subinstr to remove extra spaces from variable A.

[Andrew Musau]

You can make use of the functions -strtrim- and -stritrim- and avoid including spaces in the local.

di strtrim(stritrim("   Abc      Pregnacy   tests done   " ))

Res.:

. di strtrim(stritrim("   Abc      Pregnacy   tests done   " ))
Abc Pregnacy tests done

See

help strtrim()
help stritrim()

[Clyde Schechter]

Re #4. I think you misunderstood the thrust of my response in #2 (and, at the risk of putting words in his mouth, Dan Klein's at #3). What we showed is that, in fact, the local macro was intact and does include the extra spaces. It was just being improperly shown by -macro list-. If your code was not working, then there is some other reason for it--not the mismatch of blank spaces between the variable and the macro.

That said, I do agree that it makes more sense to clean up the string variable and eliminate superfluous blanks, as suggested by Andrew Musau in #5.