Question

具有2个输入的函数本身可以正常运行，并且可以在行上循环运行，但是在使用mutate时却发现它是必需的。我的意思是“给出正确答案的###循环”。 “ ###出现错误消息的地方”是行不通的。 eff1的第一行是正确的，但其余行已使用第一行中的s值进行了四舍五入。为什么变异不能起作用？

install.packages("reprex") 
library(reprex)
library(tidyverse)

### Digit extraction
extract_digit <- function(x, n) {
  floor(x / 10^(ceiling(log10(x)) - n )) -  
    floor(x / 10^(ceiling(log10(x)) - n + 1)) * 10
}

### Round 2 numbers "effectively"
effective_digits1 <- function(x, y)
{
  output <- vector("double", 1)  
  n <- floor(log10(x) + 1)
  for(i in 1:n)
  {
    a.i <- extract_digit(x, i)
    b.i <- extract_digit(y, i)
    if (a.i - b.i != 0)
    {
      break
    }
  }
  s = i + 1
  output <- signif(x, s)
  return(output)

}

### Function works correctly 
effective_digits1(6114, 1842)

### Dataframe on which to mutate
motor_vehicles <- data.frame("type_of_vehicle" =
                               c("Private cars and private vans",
                                 "Motorcycles, scooters and mopeds",
                                 "Public transport vehicles",
                                 "Goods",
                                 "Agricultural tractors etc",
                                 "Other vehicles"),
                              "y1961" = c(6114, 1842, 94, 1490, 481,    206),
                              "y1966" = c(9747, 1430, 96, 1611, 478, 260))

### Second df on which to mutate
motor_vehicles2 <- motor_vehicles

### Loop which gives correct answers
for (i in 1:nrow(motor_vehicles)){
  motor_vehicles$eff_1961[i] <-  effective_digits1(motor_vehicles$y1961[i], motor_vehicles$y1966[i])

}

### Where error messages appear
eff1 <- 
  motor_vehicles2 %>% 
  mutate(eff_1961 = effective_digits1(y1961, y1966))

### Loop which gives correct answers - what I'm after
### Where error messages appear - 
Warning messages:
1: In 1:n : numerical expression has 6 elements: only the first used
2: In if (a.i - b.i != 0) { :
  the condition has length > 1 and only the first element will be used

突变拒绝功能包含一个循环

0 个答案: