I have an excel file with daily data of temperature from 1903-2018. I would like to re-organize these data. For example the data begins in 1903 and you can see in the first attached file that 2 columns are shown : 1st: the month with daily (1 to 31) and 2nd(Temperature; TAM). I want to make 12 columns for the months for each year (2nd attached file). Its easy to do by hand, but it goes from 1903 to 2018...
So it would be a hard thing to do by hand. Can someone help me to code this (in R)?