how to assign a number to a countrycode (string variable) in a large panel data set

[Nico Ochmann]

Hi Gentlemen,

I have another probably rather straightforward question. I think I know how to do it, but I am looking for the most efficient way given that I have a large panel data set.
I would like to add to the countrycode ALB, DZA, etc. a new variable call it countrynumber that assigns any number, it can be 1, 2, etc. to the countrycode.
( ALB=1, and all DZA=2 and so forth).

Thanks a lot!

Nico

* Example generated by -dataex-. To install: ssc install dataex
clear
input str34 country int year str3 countrycode
"Albania" 1950 "ALB"
"Albania" 1951 "ALB"
"Albania" 1952 "ALB"
"Albania" 1953 "ALB"
"Albania" 1954 "ALB"
"Albania" 1955 "ALB"
"Albania" 1956 "ALB"
"Albania" 1957 "ALB"
"Albania" 1958 "ALB"
"Albania" 1959 "ALB"
"Albania" 1960 "ALB"
"Albania" 1961 "ALB"
"Albania" 1962 "ALB"
"Albania" 1963 "ALB"
"Albania" 1964 "ALB"
"Albania" 1965 "ALB"
"Albania" 1966 "ALB"
"Albania" 1967 "ALB"
"Albania" 1968 "ALB"
"Albania" 1969 "ALB"
"Albania" 1970 "ALB"
"Albania" 1971 "ALB"
"Albania" 1972 "ALB"
"Albania" 1973 "ALB"
"Albania" 1974 "ALB"
"Albania" 1975 "ALB"
"Albania" 1976 "ALB"
"Albania" 1977 "ALB"
"Albania" 1978 "ALB"
"Albania" 1979 "ALB"
"Albania" 1980 "ALB"
"Albania" 1981 "ALB"
"Albania" 1982 "ALB"
"Albania" 1983 "ALB"
"Albania" 1984 "ALB"
"Albania" 1985 "ALB"
"Albania" 1986 "ALB"
"Albania" 1987 "ALB"
"Albania" 1988 "ALB"
"Albania" 1989 "ALB"
"Albania" 1990 "ALB"
"Albania" 1991 "ALB"
"Albania" 1992 "ALB"
"Albania" 1993 "ALB"
"Albania" 1994 "ALB"
"Albania" 1995 "ALB"
"Albania" 1996 "ALB"
"Albania" 1997 "ALB"
"Albania" 1998 "ALB"
"Albania" 1999 "ALB"
"Albania" 2000 "ALB"
"Albania" 2001 "ALB"
"Albania" 2002 "ALB"
"Albania" 2003 "ALB"
"Albania" 2004 "ALB"
"Albania" 2005 "ALB"
"Albania" 2006 "ALB"
"Albania" 2007 "ALB"
"Albania" 2008 "ALB"
"Albania" 2009 "ALB"
"Albania" 2010 "ALB"
"Albania" 2011 "ALB"
"Albania" 2012 "ALB"
"Albania" 2013 "ALB"
"Albania" 2014 "ALB"
"Algeria" 1950 "DZA"
"Algeria" 1951 "DZA"
"Algeria" 1952 "DZA"
"Algeria" 1953 "DZA"
"Algeria" 1954 "DZA"
"Algeria" 1955 "DZA"
"Algeria" 1956 "DZA"
"Algeria" 1957 "DZA"
"Algeria" 1958 "DZA"
"Algeria" 1959 "DZA"
"Algeria" 1960 "DZA"
"Algeria" 1961 "DZA"
"Algeria" 1962 "DZA"
"Algeria" 1963 "DZA"
"Algeria" 1964 "DZA"
"Algeria" 1965 "DZA"
"Algeria" 1966 "DZA"
"Algeria" 1967 "DZA"
"Algeria" 1968 "DZA"
"Algeria" 1969 "DZA"
"Algeria" 1970 "DZA"
"Algeria" 1971 "DZA"
"Algeria" 1972 "DZA"
"Algeria" 1973 "DZA"
"Algeria" 1974 "DZA"
"Algeria" 1975 "DZA"
"Algeria" 1976 "DZA"
"Algeria" 1977 "DZA"
"Algeria" 1978 "DZA"
"Algeria" 1979 "DZA"
"Algeria" 1980 "DZA"
"Algeria" 1981 "DZA"
"Algeria" 1982 "DZA"
"Algeria" 1983 "DZA"
"Algeria" 1984 "DZA"
end

[Nick Cox]

help egen

egen countrynumber = group(countrycode), label

[Nico Ochmann]

Thank you very much Nick!

All the best!

Nico