Dear all,

I am trying to replace country pair value equal to other countries pai. I start presenting my data:



Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input str5(exp imp) double regulatory_distance float(eu_imp eu_exp) double year
"EST" "MAR"                  . 0 1 2010
"EST" "MAR"                  . 0 1 2009
"EST" "CZE"                  0 1 1 2007
"EST" "HUN"                  0 1 1 2011
"EST" "CRI"                  . 0 1 2006
"EST" "SVK"                  0 1 1 2006
"EST" "CAN"                  . 0 1 2009
"EST" "ROU"                  0 1 1 2005
"EST" "IND"                  . 0 1 2015
"EUN" "SGP"                  . 0 0 2006
"EUN" "VNM" .21107634373645426 0 0 2012
"EUN" "MEX"                  . 0 0 2005
"EUN" "CHN" .23667761891316066 0 0 2013
"EUN" "MYS" .19354031367918476 0 0 2013
"EUN" "SAU"                  . 0 0 2007
"EUN" "HKG"                  . 0 0 2005
"EUN" "CHN"                  . 0 0 2008
"EUN" "USA"   .210032856739482 0 0 2013
"EUN" "PER"                  . 0 0 2006
"EUN" "JPN"  .1901904664116847 0 0 2013
"EUN" "JPN" .14459803162667256 0 0 2009
"EUN" "RUS" .17608094928478543 0 0 2012
"EUN" "BRA"                  . 0 0 2008
"EUN" "MAR" .18337087675925984 0 0 2014
"EUN" "SGP"                  . 0 0 2005
"EUN" "KAZ"                  . 0 0 2005
"EUN" "TUR"                  . 0 0 2006
"EUN" "BRA" .26726403337667964 0 0 2012
"EUN" "NZL" .19415772648461205 0 0 2012
"EUN" "TUR"                  . 0 0 2011
"EUN" "HKG" .15265029296665403 0 0 2010
"EUN" "MAR" .17806539878630256 0 0 2012
"EUN" "SGP"                  . 0 0 2008
"EUN" "CHE" .24210785369305074 0 0 2015
"EUN" "BRN"                  . 0 0 2011
"EUN" "BRA"                  . 0 0 2005
"EUN" "BRN" .19716259545337608 0 0 2014
"EUN" "PER"                  . 0 0 2005
"EUN" "NZL"                  . 0 0 2008
"EUN" "BRA" .24336319068155848 0 0 2009
"EUN" "KHM" .21902091460771564 0 0 2012
"EUN" "PHL"                  . 0 0 2005
"EUN" "BRN"                  . 0 0 2006
"EUN" "NZL"                  . 0 0 2007
"EUN" "THA" .18668583434700872 0 0 2009
"EUN" "PHL" .21881440920417142 0 0 2015
"EUN" "HKG"                  . 0 0 2008
"EUN" "USA"  .1983230431329904 0 0 2010
"EUN" "PER"  .2220855739124433 0 0 2014
"EUN" "CHL"  .1847298981361075 0 0 2012
"EUN" "KOR" .14552465713243237 0 0 2010
end

regulatory distance is a bilateral index that ranges from 0 to 1; eu_imp (eu_exp) is a dummy variable equal to 1 if the importer (exporter) is a European country, 0 otherwise. The problem is that this index (regulatory distance) does present values for European Union as a whole (EUN) but it does not for single European countries (ex: EST, ITA, FRA,...). Thus, I would like to replace the bilateral value of all European importers (eu_imp =1) equal to the correspondent bilateral values for EUN. For instance, from this:
importer exporter regulatory distance eu_imp eu_exp year
ITA USA . 1 0 2010
ITA ZAF . 1 0 2010
RUS USA 0.46 0 0 2010
EUN USA 0.25 1 0 2010
EUN ZAF 0.36 1 0 2010

to this
importer exporter regulatory distance eu_imp eu_exp year
ITA USA 0.25 1 0 2010
ITA ZAF 0.36 1 0 2010
RUS USA 0.46 0 0 2010
EUN USA 0.25 1 0 2010
EUN ZAF 0.36 1 0 2010

I am really confused about how to get this result. Since I have been stuck on this for a long time, I hope there is someone who can help to solve this issue.