r - Select list of columns from a data frame using dplyr and select_() -

i'm trying use following function extract columns data frame:

library('dplyr') desired_columns = c(   'a',   'b',   'c') extract_columns <- function(data) {   extracted_data <- data %>%     select_(desired_columns)   return(extracted_data) } 

but when try it, don't expect:

> df <- data.frame(a=1:5, b=1:5, c=1:5, d=1:5) > df   b c d 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5 > extract_columns(df)   1 1 2 2 3 3 4 4 5 5 

i seem getting first column , can't figure out i'm doing wrong. how can requested columns?

you missing .dots argument in select_:

extract_columns <- function(data) {     extracted_data <- data %>%         select_(.dots = desired_columns)     return(extracted_data) }  extract_columns(df)   b c 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5