Hello, i have following problem and I hope you can help me a little bit My dataframe looks like: df a m d typ value 1950 1 1 5 -4.1 1950 1 2 9 2.7 1950 1 3 3 -1.3 1950 1 4 5 -1.9 1950 1 5 2 0.2 1950 1 6 8 0.5 1951 1 1 4 1.3 .... It consists by daily observations from 1950- 2009. Now, I get with.... for (i in df$V5) neu <- tapply(df[,5],list(df$V4,df$V1),mean) the yearly means of the types (1-18) for every year. The new df looks like: new typ 1950 1951 1952 1953 1954 1955 1956 ... 2009 1 0.40588235 -0.1714286 -1.8111111 5.4000000 -0.9555556 2.65833333 2 -3.17777778 1.4130435 -0.9166667 -4.9000000 0.2900000 3.54285714 3 0.08888889 -2.0000000 -2.9666667 2.2000000 -1.8600000 -0.50000000 ... 18 Now, i would like to generate a timeseries with the means, according to the different types. For example: For all days in the year 1950 with the typ 1, I would like to write the mean value for Typ 1 in year 1950. In year 1951 I would like to write the mean value for typ 1 in 1951 etc. (for all 18 types) The output should look like as following: erg a m d typ value mean_typ_year 1950 1 1 1 -4.1 0,4 1950 1 2 2 2.7 Mean (Typ2 1950) 1950 1 3 1 -1.3 0,4 1950 1 4 5 -1.9 Mean (Typ5 1950) 1950 1 5 2 0.2 ... 1950 1 6 8 0.5 ... 1951 1 1 1 1.3 -0,17 1951 1 2 2 2.1 Mean (Typ2 1951) .... I hope you can help me by solving this problem Best regards, Marko -- View this message in context: http://r.789695.n4.nabble.com/Mean-and-modelling-values-tp3686341p3686341.html Sent from the R help mailing list archive at Nabble.com.