code_01_table_to_wide.R

library(reshape2)

# Data
dat = data.frame(
    year = c(2019,2019,2019,2019,2019,2019),
    month = c(4,5,6,4,5,6),
    sex_code = c("M","M","M","F","F","F"),
    value1 = c(1,6,32,5,3,21),
    value2 = c(5,3,8,1,1,4)
)
dat

##   year month sex_code value1 value2
## 1 2019     4        M      1      5
## 2 2019     5        M      6      3
## 3 2019     6        M     32      8
## 4 2019     4        F      5      1
## 5 2019     5        F      3      1
## 6 2019     6        F     21      4

# To wide
dat = melt(dat, id.vars = c("year", "month", "sex_code"))
dat = dcast(dat, ... ~ variable + sex_code, value.var = "value")
dat

##   year month value1_F value1_M value2_F value2_M
## 1 2019     4        5        1        1        5
## 2 2019     5        3        6        1        3
## 3 2019     6       21       32        4        8