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From |
Nick Cox <njcoxstata@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Use extended functions outside of macro assignment? |

Date |
Wed, 7 Sep 2011 07:06:33 +0100 |

The logic of -list- with -if- is like any other command. Consider list if 2 == 2 2 == 2 is (vacuously) true when considered for observation 1, for observation 2, and so on, so every variable and every observation will be -list-ed. The same will be true of your syntax. If your condition is true, i.e. there is a match, then everything will be listed. What I think you want is a two-step operation to Stata. First, you produce a varlist, then you supply that varlist to some command. In official Stata, check out -ds- and in user-written Stata check out -findname-. -search findame- in an up-to-date Stata will find an article and an update in the Stata Journal; use the update to get the software and read the article! Nick On Tue, Sep 6, 2011 at 9:06 PM, James Sams <sams.james@gmail.com> wrote: > I keep running into situations where I would like to use an extended function > as a part of a function call, e.g. in a conditional statement. I thought I had > seen syntax to do this before, but I cannot find this now. > > For example, let's say I wanted to operate on a set of observations dependent > upon some characteristic of a value label, say that the value label matches > some regular expression. How can I do this? I specifically cannot pull the value > label into a string variable with decode due to the size of the dataset: > > Something like this: > list if regexm("`: label (varname)'", "my_regex") > > or say I want to operate on a set of ids I have stored in a local macro "ids": > > list if `: list posof id in ids' * * 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/

**Follow-Ups**:**Re: st: Use extended functions outside of macro assignment?***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: Use extended functions outside of macro assignment?***From:*James Sams <sams.james@gmail.com>

**References**:**st: Use extended functions outside of macro assignment?***From:*James Sams <sams.james@gmail.com>

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