Conditional operation on multiple columns from two data frames
tsippel wrote:
The suggestion below was made. df1$Date <- as.Date(df1$Date) df2$Date <- as.Date(df2$Date) ifelse(df1$ID==df2$ID & df1$Date-df2$Date<0.5,df1$y-df2$y, NA) However, because my dataframe rows do not align, I need the conditionals to be tested on every combination of cells. I'm starting to think I need to use tapply? Tim
I'd look at outer() or try a merge() before the operation to get things aligned. It is not clear to me what form of output you desire if you look at "every combination of cells".
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