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From |
"Impavido, Gregorio" <GImpavido@imf.org> |

To |
"statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: Need Help with converting String Variables to Numeric Variables |

Date |
Tue, 19 Jun 2012 11:01:52 -0400 |

In addition to the condition suggested by Nick, you could try the substitution before you destring. Make a list of target entries to be substituted with gen var2 = var // not to alter the original data tab var2 if regexm(var2, "[^0-9 .]") // or tab var2 if missing(real(var2)) and then replace replace var2 = "0" if var2=="targetvalues" clearly not convenient if you happen to have many target values as you would have many replace entries. However it would spare you the use of -force- in -destring- (my personal lack of confidence with that option) -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox Sent: Tuesday, June 19, 2012 4:25 AM To: statalist@hsphsun2.harvard.edu Subject: Re: st: Need Help with converting String Variables to Numeric Variables The table I suggested was the wrong way round. tab numvar if missing(strvar) should be tab strvar if missing(numvar) but the mention of -if missing(strvar)- might have alerted you to the key trick: making your conversions conditional on the value of a variable. For example, empty strings "", one or more spaces " ", " ", etc., periods ".", stray text "foo", inequalities such as "<4" will all map to numeric missing under -destring, force-. It may be, at the easiest, that replace numvar = 0 if strpos(strvar, "<") == 1 is enough to get what you want, but you need to look at your data. On Tue, Jun 19, 2012 at 3:38 AM, Dudekula, Anwar <dudekulaan@upmc.edu> wrote: > Dear Nick and Daniel, > > Thanks a lot for the response. > > Unfortunately, I have missing values in the original variable. > > Hence the new variable generated with destring command and force option generates new additional missing values in addition to missing values generated corresponding to the missing values in original variable > > The practical problem with this issues is that the original variable is a biomarker and a missing value is being created for an observation like "<0.01" in original variable. > > In stata missing value is a huge number but infact this number should be equal to zero Nick Cox [njcoxstata@gmail.com] > I agree with Daniel. But I would check what is being mapped to zero. > > destring numvar, force gen(strvar) > tab numvar if missing(strvar) > On Mon, Jun 18, 2012 at 11:58 PM, daniel klein > <klein.daniel.81@googlemail.com> wrote: > >> Can't you just -destring- your string variable, specifying the -force- >> option, and -replace- the created missing values with 0 in the new >> variable? Or am I missing something here? > > Anwar > >> I am working on a data set of a hospital where one of the variables >> has string values as observations . >> >> I am able to convert numeric string values to numeric values using >> destring command. >> >> But I have some of the observations as "< 4", "<0.04","less than 0.1" >> which needs to be converted to zero . >> >> In Stata we have option to convert nonmumeric values to missing values >> , but I need to convert them to Zero . * * 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/ * * 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**:**Re: st: Need Help with converting String Variables to Numeric Variables***From:*daniel klein <klein.daniel.81@googlemail.com>

**Re: st: Need Help with converting String Variables to Numeric Variables***From:*Nick Cox <njcoxstata@gmail.com>

**RE: st: Need Help with converting String Variables to Numeric Variables***From:*"Dudekula, Anwar" <dudekulaan@upmc.edu>

**Re: st: Need Help with converting String Variables to Numeric Variables***From:*Nick Cox <njcoxstata@gmail.com>

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