Defines new variables under condition for data frame
dtransform(data, ...)is data frame
new variable definitions including possible if condition
data(mena)
xx <- dtransform(mena,ll=log(agemena)+twinnum)
xx <- dtransform(mena,ll=log(agemena)+twinnum,agemena<15)
xx <- dtransform(xx ,ll=100+agemena,ll2=1000,agemena>15)
dsummary(xx,ll+ll2~I(agemena>15))
#> I(agemena > 15): FALSE
#> ll ll2
#> Min. :3.227 Min. : NA
#> 1st Qu.:3.557 1st Qu.: NA
#> Median :3.702 Median : NA
#> Mean :4.048 Mean :NaN
#> 3rd Qu.:4.557 3rd Qu.: NA
#> Max. :4.707 Max. : NA
#> NA's :1859
#> ------------------------------------------------------------
#> I(agemena > 15): TRUE
#> ll ll2
#> Min. :115.0 Min. :1000
#> 1st Qu.:115.3 1st Qu.:1000
#> Median :115.5 Median :1000
#> Mean :115.7 Mean :1000
#> 3rd Qu.:115.9 3rd Qu.:1000
#> Max. :118.2 Max. :1000