问题
I have a data.frame with several variables for a universe of stocks and I want to create a subset of this data frame that filters the data I have for just the S&P 500 stocks.
I created a list of all the stocks in the S&P 500, and I basically want the program to go through my data frame and copy over all the rows which contain an item from my S&P 500 list. I tried using a for-loop and that crashed my RStudio, so if anyone knows if there's a way I can do this, please let me know!
This code works for just one stock in the S&P500, but I want it to work for all of them. t is what I named my data frame.
sp500dataonly <- filter(t, SYMBOL == "AAPL")
All help is greatly appreciated!
回答1:
Say you have a set (technically not a list in R. It is actually a vector.) of the stocks you want to include called myStocks
Then you can subset by saying:
sp500dataonly<- t[t$SYMBOL %in% myStocks,]
example:
mySpecies <-c("versicolor","virginica" )
iris[iris$Species %in% mySpecies,]
Will give the subset we are after.
来源：https://stackoverflow.com/questions/37635085/how-to-subset-dataframe-using-string-values-from-a-list