rrbindnewrow

How to add certain number of rows based on values on the rows of another variable

date        time    td  number
20150102    80000   -1  0
20150102    80001   -1  2
20150102    80002   1   0
20150102    80003   1   3
20150102    80004   -1  0

I need to create append number of rows based on variable "number". And let date and time be the same as the numbered rows, while the variable td=0. I want the data like this:

date        time    td  number
20150102    80000   -1  0
20150102    80001   -1  2
20150102    80002   1   0
20150102    80003   1   3
20150102    80004   -1  0
20150102    80001   0   NA 
20150102    80001   0   NA
20150102    80003   0   NA
20150102    80003   0   NA
20150102    80003   0   NA
Solution

  • I'd generate each column, then bind them into a data frame, then bind them to the original dataframe! No looping required.

    Assuming your data frame is called df

    #Create the date and time using the number column directly.
date <- rep(df$date, times = df$number)
time <- rep(df$time, times = df$number)

#Combine these fields into a data frame and set td to all 0s and number to all NAs
appenddf <- data.frame(date = date, time = time, td = 0, number = NA)

#Bind the data for appending to the original data frame
df <- rbind(df, appenddf)