Quickly create new columns in dataframe using lists - R - r

Question

I have a data containing quotations of indexes (S&P500, CAC40,...) for every 5 minutes of the last 3 years, which make it quite huge. I am trying to create new columns containing the performance of the index for each time (ie (quotation at [TIME]/quotation at yesterday close) -1) and for each index. I began that way (my data is named temp):
listIndexes<-list("CAC","SP","MIB") # there are a lot more
listTime<-list(900,905,910,...1735) # every 5 minutes
for (j in 1:length(listTime)){
Time<-listTime[j]
for (i in 1:length(listIndexes)) {
Index<-listIndexes[i]
temp[[paste0(Index,"perf",Time)]]<-temp[[paste0(Index,Time)]]/temp[[paste0(Index,"close")]]-1
# other stuff to do but with the same concept
}
}
but it is quite long. Is there a way to get rid of the for loop(s) or to make the creation of those variables quicker ? I read some stuff about the apply functions and the derivatives of it but I do not see if and how it should be used here.
My data looks like this :
date CACcloseyesterday CAC1000 CAC1005 ... CACclose ... SP1000 ... SPclose
20140105 3999 4000 40001.2 4005 .... 2000 .... 2003
20140106 4005 4004 40003.5 4002 .... 2005 .... 2002
...
and my desired output would be a new column (more eaxcatly a new column for each time and each index) which would be added to temp
date CACperf1000 CACperf1005... SPperf1000...
20140106 (4004/4005)-1 (4003.5/4005)-1 .... (2005/2003)-1 # the close used is the one of the day before
idem for the following day
i wrote (4004/4005)-1 just to show the calcualtio nbut the result should be a number : -0.0002496879

Answer 1

It looks like you want to generate every combination of Index and Time. Each Index-Time combination is a column in temp and you want to calculate a new perf column by comparing each Index-Time column against a specific Index close column. And your problem is that you think there should be an easier (less error-prone) way to do this.
We can remove one of the for-loops by generating all the necessary column names beforehand using something like expand.grid.
listIndexes <-list("CAC","SP","MIB")
listTime <- list(900, 905, 910, 915, 920)
df <- expand.grid(Index = listIndexes, Time = listTime,
stringsAsFactors = FALSE)
df$c1 <- paste0(df$Index, "perf", df$Time)
df$c2 <- paste0(df$Index, df$Time)
df$c3 <- paste0(df$Index, "close")
head(df)
#> Index Time c1 c2 c3
#> 1 CAC 900 CACperf900 CAC900 CACclose
#> 2 SP 900 SPperf900 SP900 SPclose
#> 3 MIB 900 MIBperf900 MIB900 MIBclose
#> 4 CAC 905 CACperf905 CAC905 CACclose
#> 5 SP 905 SPperf905 SP905 SPclose
#> 6 MIB 905 MIBperf905 MIB905 MIBclose
Then only one loop is required, and it's for iterating over each batch of column names and doing the calculation.
for (row_i in seq_len(nrow(df))) {
this_row <- df[row_i, ]
temp[[this_row$c1]] <- temp[[this_row$c2]] / temp[[this_row$c3]] - 1
}
An alternative solution would also be to reshape your data into a form that makes this transformation much simpler. For instance, converting into a long, tidy format with columns for Date, Index, Time, Value, ClosingValue column and directly operating on just the two relevant columns there.