I have one R dataframe
Customer Month BaseVolume IncrementalVolume TradeSpend
10 Jan 11 1 110
10 Feb 12 2 120
20 Jan 21 7 210
20 Feb 22 8 220
Which I want to convert it like this,
Customer Jan Feb
10 BaseVolume 11 BaseVolume 12
IncrementalVolume 1 IncrementalVolume 2
TradeSpend 110 TradeSpend 120
20 BaseVolume 21 BaseVolume 22
IncrementalVolume 7 IncrementalVolume 8
TradeSpend 210 TradeSpend 220
I tried dcast (reshape) but I couldn't get this result. Please help me out
Although there is already an answer, I feel it can improved in some respect to come closer to the expected output:
Jan, Febdcast()We'll start with reshaping the input data from wide to long format but make sure that Month will appear in the correct order:
molten <- melt(dt1, id.vars = c("Customer", "Month"))
# turn Month into factor with levels in the given order
molten[, Month := forcats::fct_inorder(Month)]
Now, a new text column is created in long format before the call to dcast():
molten[, text := paste(variable, value)]
dcast(molten, Customer + variable ~ Month, value.var = "text")[, variable := NULL][]
# Customer Jan Feb
#1: 10 BaseVolume 11 BaseVolume 12
#2: 10 IncrementalVolume 1 IncrementalVolume 2
#3: 10 TradeSpend 110 TradeSpend 120
#4: 20 BaseVolume 21 BaseVolume 22
#5: 20 IncrementalVolume 7 IncrementalVolume 8
#6: 20 TradeSpend 210 TradeSpend 220
The result is similar to this answer but has the months in the expected order.
N.B. Unfortunately, the approach to collapse also the rows per Customer doesn't work as line breaks aren't respected when printed:
dcast(molten, Customer ~ Month, value.var = "text", paste0, collapse = "\n")
# Customer Jan Feb
#1: 10 BaseVolume 11\nIncrementalVolume 1\nTradeSpend 110 BaseVolume 12\nIncrementalVolume 2\nTradeSpend 120
#2: 20 BaseVolume 21\nIncrementalVolume 7\nTradeSpend 210 BaseVolume 22\nIncrementalVolume 8\nTradeSpend 220
The text column can be left aligned by padding white space to the right (the minimum lengths is determined by the character length of the longest string):
molten[, text := paste(variable, value)]
molten[, text := stringr::str_pad(text, max(nchar(text)), "right")]
dcast(molten, Customer + variable ~ Month, value.var = "text")[, variable := NULL][]
# Customer Jan Feb
#1: 10 BaseVolume 11 BaseVolume 12
#2: 10 IncrementalVolume 1 IncrementalVolume 2
#3: 10 TradeSpend 110 TradeSpend 120
#4: 20 BaseVolume 21 BaseVolume 22
#5: 20 IncrementalVolume 7 IncrementalVolume 8
#6: 20 TradeSpend 210 TradeSpend 220
Or, the text column can be aligned in itself:
fmt <- stringr::str_interp("%-${n}s %3i", list(n = molten[, max(nchar(levels(variable)))]))
molten[, text := sprintf(fmt, variable, value)]
dcast(molten, Customer + variable ~ Month, value.var = "text")[, variable := NULL][]
# Customer Jan Feb
#1: 10 BaseVolume 11 BaseVolume 12
#2: 10 IncrementalVolume 1 IncrementalVolume 2
#3: 10 TradeSpend 110 TradeSpend 120
#4: 20 BaseVolume 21 BaseVolume 22
#5: 20 IncrementalVolume 7 IncrementalVolume 8
#6: 20 TradeSpend 210 TradeSpend 220
Here, the format to be used in sprintf() is also created dynamically by using string interpolation:
fmt
#[1] "%-17s %3i"
Note that the character length of the longest level of variable is used here as melt() has turned variable to factor by default.
The answer could have been much simpler as the latest versions of data.table allow to reshape multiple columns simultaneously:
molten <- melt(dt1, id.vars = c("Customer", "Month"))
molten[, Month := forcats::fct_inorder(Month)]
dcast(molten, Customer + variable ~ Month, value.var = c("variable", "value"))
# Customer variable variable.1_Jan variable.1_Feb value_Jan value_Feb
#1: 10 BaseVolume BaseVolume BaseVolume 11 12
#2: 10 IncrementalVolume IncrementalVolume IncrementalVolume 1 2
#3: 10 TradeSpend TradeSpend TradeSpend 110 120
#4: 20 BaseVolume BaseVolume BaseVolume 21 22
#5: 20 IncrementalVolume IncrementalVolume IncrementalVolume 7 8
#6: 20 TradeSpend TradeSpend TradeSpend 210 220
but unfortunately it is lacking an option to easily reorder the columns in alternating order, i.e., all columns belonging to Jan, then Feb etc.