R函数中的复数和缺失参数

我正在为我的R在线课程解决一项任务。任务是编写一个函数，用拉格朗日分解法求解二次方程，或：

x1<--p/2+sqrt((p/2)^2-q)
x2<--p/2-sqrt((p/2)^2-q)

1） 如何编写该函数，使其假定为TRUE（不带“”），而任何非数字的内容都视为非数字？ 2） 基本情况下，工程。 3） 如何编写函数，使其解方程并打印复数，同时警告数字是复数（warning（））？

类似的内容

quadraticEquation <- function(p, q){
  ## ------------------------% chek the arguments %---------------------------##
  if(
    missing(p) | missing(q)                              # if any of arguments is 
  ){                                                     # missing - stop.
    stop("[!] There are argument/s missing")
  }
  else if(
    !is.numeric(p) | !is.numeric(q) | any(is.na(c(p, q))) # !is.numeric(c(1, T))
  ){                                                     # returns TRUE - conver-    
    stop("[!] Argument/s p or/and q are not numeric")    # tion to the same type
  }
  ## --------------------% main part of the function %--------------------------##  
  r2 <- p^2 - 4*q                                        # calculate r^2,
  if(r2 < 0){                                            # if r2 < 0 (convert) it 
    warning("equation has complex roots")                # to complex and warn
    r2 <- as.complex(r2)
  }
                                                         # return named roots
  setNames(c(-1, 1) * sqrt(r2)/2 - p/2, c("x1", "x2"))
}

quadraticEquation()                                      # No arguments provided
#Error in quadraticEquation() : [!] There are argument/s missing
quadraticEquation(p = 4)                                 # Argument q is missing
#Error in quadraticEquation(p = 4) : [!] There are argument/s missing
quadraticEquation(p = TRUE, q = 7)                       # p is logical
#Error in quadraticEquation(p = TRUE, q = 7) : 
#[!] Argument/s p or/and q are not numeric
quadraticEquation(p = NA, q = 7)                         # p is NA
#Error in quadraticEquation(p = NA, q = 7) : 
#[!] Argument/s p or/and q are not numeric
quadraticEquation(p = 7, q = -4)                         # real roots
#        x1         x2 
#-7.5311289  0.5311289 
quadraticEquation(p = -4, q = 7)                         # complex roots
#         x1          x2 
#2-1.732051i 2+1.732051i
#Warning message:
#In quadraticEquation(p = -4, q = 7) : equation has complex roots

---

quadraticEquation当你写
is.numeric（c（p，q））
时，R首先计算
c（p，q）
，然后再确定它是否是数字。特别是如果
p=TRUE
和
q=3
，则
c（p，q）
被提升为更高的类型：
c（1，3）

这是一个矢量化的解决方案，因此如果
p
和
q
是矢量而不是标量，那么结果也是矢量

quadraticEquation <- function(p, q) {
  if (missing(p)) {
    stop("`p` is missing.")
  }
  if (missing(q)) {
    stop("`q` is missing.")
  }
  if (!is.numeric(p)) {
    stop("`p` is not numeric.")
  }
  if (!is.numeric(q)) {
    stop("`q` is not numeric.")
  }
  if (anyNA(p)) {
    stop("`p` contains NAs.")
  }
  if (anyNA(q)) {
    stop("`q` contains NAs.")
  }

  R <- p^2 / 4 - q

  if (min(R) < 0) {
    R <- as.complex(R)
    warning("Returning complex values.")
  }

  list(x1 = -p / 2 + sqrt(R),
       x2 = -p / 2 - sqrt(R))
}

quadraticEquation绝妙的解决方案！我可以问一下，如果x1和x2相等（例如，当p=-4和q=4时），如何返回只有一个元素（x1）的向量吗？也许可以尝试
unique（）
它将返回唯一的值，因此
unique（c（1，1））返回
1`不起作用，在集合名中返回错误：缺少参数“nm”，没有默认值。（这个论点是什么？）是的，对不起，思维不好。所以像这样划分：-计算根：
根
quadraticEquation <- function(p, q){
  ## ------------------------% chek the arguments %---------------------------##
  if(
    missing(p) | missing(q)                              # if any of arguments is 
  ){                                                     # missing - stop.
    stop("[!] There are argument/s missing")
  }
  else if(
    !is.numeric(p) | !is.numeric(q) | any(is.na(c(p, q))) # !is.numeric(c(1, T))
  ){                                                     # returns TRUE - conver-    
    stop("[!] Argument/s p or/and q are not numeric")    # tion to the same type
  }
  ## --------------------% main part of the function %--------------------------##  
  r2 <- p^2 - 4*q                                        # calculate r^2,
  if(r2 < 0){                                            # if r2 < 0 (convert) it 
    warning("equation has complex roots")                # to complex and warn
    r2 <- as.complex(r2)
  }
                                                         # return named roots
  setNames(c(-1, 1) * sqrt(r2)/2 - p/2, c("x1", "x2"))
}

quadraticEquation()                                      # No arguments provided
#Error in quadraticEquation() : [!] There are argument/s missing
quadraticEquation(p = 4)                                 # Argument q is missing
#Error in quadraticEquation(p = 4) : [!] There are argument/s missing
quadraticEquation(p = TRUE, q = 7)                       # p is logical
#Error in quadraticEquation(p = TRUE, q = 7) : 
#[!] Argument/s p or/and q are not numeric
quadraticEquation(p = NA, q = 7)                         # p is NA
#Error in quadraticEquation(p = NA, q = 7) : 
#[!] Argument/s p or/and q are not numeric
quadraticEquation(p = 7, q = -4)                         # real roots
#        x1         x2 
#-7.5311289  0.5311289 
quadraticEquation(p = -4, q = 7)                         # complex roots
#         x1          x2 
#2-1.732051i 2+1.732051i
#Warning message:
#In quadraticEquation(p = -4, q = 7) : equation has complex roots

quadraticEquation <- function(p, q) {
  if (missing(p)) {
    stop("`p` is missing.")
  }
  if (missing(q)) {
    stop("`q` is missing.")
  }
  if (!is.numeric(p)) {
    stop("`p` is not numeric.")
  }
  if (!is.numeric(q)) {
    stop("`q` is not numeric.")
  }
  if (anyNA(p)) {
    stop("`p` contains NAs.")
  }
  if (anyNA(q)) {
    stop("`q` contains NAs.")
  }

  R <- p^2 / 4 - q

  if (min(R) < 0) {
    R <- as.complex(R)
    warning("Returning complex values.")
  }

  list(x1 = -p / 2 + sqrt(R),
       x2 = -p / 2 - sqrt(R))
}