在 R 中使用 dplyr 编写一种 for 循环

Question

Is there a possibility to use a kind of for loop inside a dplyr syntax? I'm using the following syntax to check the presence of MAP<99, MAP<98 and so on until MAP<1. Not very efficient, so I like to repeat this function from MAP< [100:1].

duur2_vs_diepte <- data_blood_pressure %>%
  summarise(
    duur_tm99_2 = (sum(MAP<=99))^2,
    duur_tm98_2 = (sum(MAP<=98))^2,
    duur_tm97_2 = (sum(MAP<=97))^2,
    .......
    duur_tm4_2 = (sum(MAP<=4))^2,
    duur_tm3_2 = (sum(MAP<=3))^2,
    duur_tm2_2 = (sum(MAP<=2))^2,
    duur_tm1_2 = (sum(MAP<=1))^2
  )

Answer 1

This may work for you:

# a helping function to create each column
create_columns <- function(x, mat) {
  dt <- mat %>%
    filter(MAP <= x) %>%
    summarise(sum(MAP, na.rm = TRUE)^2)

  names(dt) <- paste0("duur_tm", x, "_2")

  dt
}

# get all results together
bind_cols(lapply(100:1, create_columns, data_blood_pressure))