functional programming - append data to dataFrame in R function -

i trying write r function adds new row existing dataframe.

here code (r newbie here):

    qrows <- data.frame( rowquery = character(0), "backtest p&l" = character(0), stringsasfactors=false)     # add row dataframe     qrows[nrow(qrows) + 1, ] <- c("sp500(vwpc) | abc(30) | qcume",  "12%")      #define function add new row dataframe     q <- function(data, y){       data[nrow(data) + 1, ] <- c(y,"88")     }     # run new function     q(qrows, "newquery")     #examine output: no new row added     qrows 

the code runs without error, no new row added.

two changes :

you need return function output , assign outputted value qrows.

qrows <- data.frame( rowquery = character(0), "backtest p&l" = character(0), stringsasfactors=false) # add row dataframe qrows[nrow(qrows) + 1, ] <- c("sp500(vwpc) | abc(30) | qcume",  "12%")  #define function add new row dataframe q <- function(data, y){   data[nrow(data) + 1, ] <- c(y,"88")   return(data)    # <---------------------------------**return data** } # run new function qrows= q(qrows, "newquery")  #<---------------------  **assign output qrows** qrows 

output

                       rowquery backtest.p.l 1 sp500(vwpc) | abc(30) | qcume          12% 2                      newquery           88 

in code, q added new row data .

note, new row added variable data local function q , not qrows.