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From |
"Jennifer S. Earl" <jearl@soc.ucsb.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
RE: st: problem creating and doing a foreach on a local of allnumeric variables in a dataset |

Date |
Wed, 27 Aug 2008 11:01:31 -0700 |

Thanks again Maarten for the additional working code and Nick for the excellent explanation. I really learned a lot.

--On Wednesday, August 27, 2008 5:20 PM +0100 Nick Cox <n.j.cox@durham.ac.uk> wrote:

Not that I have anything against -ds-, dear and sweet that it is, but just to note that there are other ways to do this: foreach var of var * { capture confirm numeric variable `var' if _rc { replace `var' = "" if `var'_error == 1 } else { replace `var' = . if `var'_error == 1 } } Occasionally I have wanted a function say -sysmiss(<arg>)- that returns string missing "" if <arg> is string and . otherwise. I am not sure if it's really a good idea! Nick n.j.cox@durham.ac.uk Nick Cox To expand a little: local num_vars r(varlist) will just put the literal text "r(varlist)" in your macro. It won't put the contents of r(varlist) in your macro. Also local num_vars r(varlist) foreach var of local `num_vars' { is equivalent to foreach var of local r(varlist) { which doesn't satisfy -foreach- because r(varlist) is not the name of a local macro. It is true that the error messages in each case are not illuminating! Nick n.j.cox@durham.ac.uk Maarten buis try: foreach var of varlist `r(varlist)' { That is: adding a "`" and a "'" around r(varlist) Jennifer S. EarlIn the middle of a program I am working on, I need to set a bunch of variables to missing, some of which are numeric and some of which are string. Since the replace command is sensitive to numeric or string, I need to do separate foreach loops. Here is what I have tried: ds , has(type numeric) local num_vars r(varlist) foreach var of local num_vars { replace `var'=. if `var'_error==1 } ds , has(type string) local string_vars r(varlist) foreach var of local string_vars { replace `var'="" if `var'_error==1 } Unfortunately, when I try this, I get the following error: time-series operators not allowed r(101); If I do instead (in case if is my foreach line that is giving me problems): ds , has(type numeric) local num_vars r(varlist) foreach var of local `num_vars' { replace `var'=. if `var'_error==1 } I get the following error: { required r(100); But, the puzzling part is that I see the right list of numeric variables displayed if I do: ds , has(type numeric) local num_vars r(varlist) display `num_vars' So, I know I am fetching the right list, I am just not able to operate on it in the foreach loop. I have tried other ways of selecting off just the numeric variables and just the string and none are working. Any suggestions? Maybe it is late and I missing something obvious?* * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

********************************* Jennifer Earl Director, Center for Information Technology and Society Associate Professor of Sociology University of California, Santa Barbara Santa Barbara, CA 93106-9430 P: (805) 893-7471 F: (805) 893-3324 ********************************* * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: problem creating and doing a foreach on a local of all numericvariables in a dataset***From:*"Jennifer S. Earl" <jearl@soc.ucsb.edu>

**Re: st: problem creating and doing a foreach on a local of all numeric variables in a dataset***From:*Maarten buis <maartenbuis@yahoo.co.uk>

**RE: st: problem creating and doing a foreach on a local of all numeric variables in a dataset***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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