使用函数创建数据框

Question

我有一个包含许多值和计算的 data.frame。其中一个值是风速。我所做的是从变化的风速中计算出不同的能量。我手动完成并逐行构建数据框，如下所示：

zz <- as.data.frame(matrix(seq(100),nrow=5,ncol=3))

zz$V1 <- c("v_in (m/s)","density p (kg/m^3)","Cd ()", "d_rotor (m)",     
         "A_rotor (m^2)")

zz$V2 <- c("2",  # wind_speed
         "1.2",      # density
         "0.00482", # Cd
         "112",     # d_rotor
         "")

zz$V3[1] <- "" # v_in
zz$V3[2] <- "" # density
zz$V3[3] <- "" # Cd
zz$V3[4] <- "" # d_rotor
zz$V3[5] <- as.numeric(pi/4*(as.numeric(zz[4,2]))^2) # A_rotor 

这只是我的data.frame的摘录，但我希望你能看到我的意图。 我现在想要的是创建始终具有更改参数的相同数据框，例如风速（比如说 3 和 4 m/s）。 同时更改多个值也很酷（假设风速 5 和密度 1 或风速 6 和密度 2）。 我试图用一个函数来解决这个问题，但它没有用。它只给了我一个值，而不是完整的数据框。

speed_vector <- c("w_sp_3" = 3, "w_sp_4" = 4)

make_speed <- function(x)

{
  zz <- as.data.frame(matrix(seq(100),nrow=5,ncol=3))

  zz$V1 <- c("v_in (m/s)","density p (kg/m^3)","Cd ()", "d_rotor (m)", 
           "A_rotor (m^2)")

  zz$V2 <- c("speed_vector[x]",  # v_in
           "1.2",      # density
           "0.00482", # Cd
           "112",     # d_rotor
           "")

  zz$V3[1] <- "" # v_in
  zz$V3[2] <- "" # density
  zz$V3[3] <- "" # Cd
  zz$V3[4] <- "" # d_rotor
  zz$V3[5] <- as.numeric(pi/4*(as.numeric(zz[4,2]))^2) # A_rotor
}

w_speed_3 <- make_speed("w_sp_3")
w_speed_4 <- make_speed("w_sp_4")

这是修改后的新代码：

speed_vector <- c("w_sp_3" = 3, "w_sp_4" = 4)
make_speed <- function(x)  
{
V1 <- c("v (m/s)","density (kg/m^3)","Cd ()", "d (m)", "A (m^2)", "N/(W*L)", 
      "length L (km)", "Width W (km)", "Height H (m)", "coefficient ()", 
      "N ()", "J_h (GW)", "J_v (GW)", "f_red ()", "v (m/s)", "J_out (GW)")

V2 <- c(speed_vector[x],  # v
      "1.2",      # density
      "0.00482", # Cd
      "112",     # d
      "",
      "4.1",   # MW/km^2
      "", "",
      "700",    # Height
      "0.44",   # coefficient
      "", "", "", "", "", "")

V3 <- c(rep("",4), 
      as.numeric(pi/4*(as.numeric(V2[4]))^2),
      rep("",1), 
      as.numeric((16172.5*0.0898)^(1/2)), 
      as.numeric((16172.5*0.0898)^(1/2)), 
      rep("",2), 
      as.numeric(16172.5*0.0898*as.numeric(V2[4])/3.075), 

as.numeric(as.numeric(V2[2])/2*as.numeric(V3[8])*1000*as.numeric(V2[9])*
   (as.numeric(V2[1])^3)/10^9),   

as.numeric((as.numeric(V2[2])*as.numeric(V2[3])*as.numeric(V3[8])*1000*   
   as.numeric(V3[7])*1000*(as.numeric(V2[1])^3))/10^9),

as.numeric(as.numeric(V2[9])+2*as.numeric(V2[3])*as.numeric(V3[7])*1000)/   
   ((as.numeric(V2[9])+2*as.numeric(V2[3])*as.numeric(V3[7])*1000)+3/2*                
   as.numeric(V3[11])/(as.numeric(V3[8])*1000)*as.numeric(V2[10])*    
   as.numeric(V3[5])), 

as.numeric(as.numeric(V3[14])^(1/3)*as.numeric(V2[1])),

as.numeric(as.numeric(V2[2])/2*(as.numeric(V3[8])*1000)*as.numeric(V2[9])*
   as.numeric(V3[15])^3/10^9))


zz <- data.frame(V1,V2,V3) 
return(zz) 
}
w_speed_3 <- make_speed("w_sp_3")
w_speed_4 <- make_speed("w_sp_4")

一个更简单的例子：

speed_vector <- c("w_sp_3" = 3, "w_sp_4" = 4)
make_speed <- function(x)  
{
V1 <- c("v (m/s)","density (kg/m^3)","Cd ()", "d (m)", "A (m^2)", "N/(W*L)",
"V(m/s)")

V2 <- c(speed_vector[x],  # v 
"1",      # density
"2", # Cd
"3",     # d
"4",   # MW/km^2
"5",    # Height
"6"   # coefficient
)

V3 <- c(as.numeric(as.numeric(V2[4]) ^ 2),
as.numeric(as.numeric(V2[1]) + as.numeric(V2[2])), 
as.numeric(as.numeric(V2[1]) * as.numeric(V2[2])), 
as.numeric(as.numeric(V2[1]) + as.numeric(V2[2]) + as.numeric(V2[3])), 
as.numeric(as.numeric(V2[2]) + as.numeric(V3[2])),   
as.numeric(as.numeric(V3[1]) + as.numeric(V3[2])))


zz <- data.frame(V1,V2,V3) 
return(zz) 
}
w_speed_3 <- make_speed("w_sp_3")
w_speed_4 <- make_speed("w_sp_4")

Answer 1

我清理了一下，如果你想要的话，请告诉我：

speed_vector <- c("w_sp_3" = 3, "w_sp_4" = 4)

make_speed <- function(x)  
{
 V1 <- c("v_in (m/s)","density p (kg/m^3)","Cd ()", "d_rotor (m)", 
             "A_rotor (m^2)")

 V2 <- c(speed_vector[x],  # v_in # it was a string in your question, but it's the only place where x was used so I figured you wanted it as a value
             "1.2",      # density
             "0.00482", # Cd
             "112",     # d_rotor
             "")
  V3 <- c(rep("",4),as.numeric(pi/4*(as.numeric(V2[4]))^2))
  zz <- data.frame(V1,V2,V3) # better to build the data.frame this way than starting with an empty one, and also yours was generating warnings because of number of element not consistent with rows and cols
  return(zz) # the important line that you were missing
}

w_speed_3 <- make_speed("w_sp_3")
w_speed_4 <- make_speed("w_sp_4")

---

编辑为您的后续问题

您现在遇到的问题完全不同。

您可能想了解函数debugonce 和debug。

通过运行：

debugonce(speed)
w_speed_3 <- make_speed("w_sp_3")

我看到错误在该行中：

V3 <- c(rep("", 4), as.numeric(pi/4 * (as.numeric(V2[4]))^2), 
    rep("", 1), as.numeric((16172.5 * 0.0898)^(1/2)), as.numeric((16172.5 * 
        0.0898)^(1/2)), rep("", 2), as.numeric(16172.5 * 0.0898 * 
        as.numeric(V2[4])/3.075), as.numeric(as.numeric(V2[2])/2 * 
        as.numeric(V3[8]) * 1000 * as.numeric(V2[9]) * (as.numeric(V2[1])^3)/10^9), 
    as.numeric((as.numeric(V2[2]) * as.numeric(V2[3]) * as.numeric(V3[8]) * 
        1000 * as.numeric(V3[7]) * 1000 * (as.numeric(V2[1])^3))/10^9), 
    as.numeric(as.numeric(V2[9]) + 2 * as.numeric(V2[3]) * as.numeric(V3[7]) * 
        1000)/((as.numeric(V2[9]) + 2 * as.numeric(V2[3]) * as.numeric(V3[7]) * 
        1000) + 3/2 * as.numeric(V3[11])/(as.numeric(V3[8]) * 
        1000) * as.numeric(V2[10]) * as.numeric(V3[5])), as.numeric(as.numeric(V3[14])^(1/3) * 
        as.numeric(V2[1])), as.numeric(as.numeric(V2[2])/2 * 
        (as.numeric(V3[8]) * 1000) * as.numeric(V2[9]) * as.numeric(V3[15])^3/10^9))

仔细看，我看到你在调用 V3 来定义 V3，但是 V3 不存在，所以函数停止并出现错误。

我不知道您要做什么，但是您不能在右侧使用自身启动变量。

Answer 2

编辑：更新了两个选项的后续请求。

考虑这种方法；将参数存储在列中更习惯：

speed_racer <- function(v_in = NULL, density = NULL, Cd = NULL, d_rotor = NULL) {
  scenario <<- data.frame(v_in = c("(m/s)", v_in), density = c("(kg/m^3)", density), 
                          Cd = c("()", Cd), d_rotor = c("(m)", d_rotor), 
                          A_rotor = c("(m^2)", as.numeric(pi/4*(as.numeric(d_rotor)^2))))
}

speed_racer(v_in = 2.0, density = 1.2, Cd = 0.00482, d_rotor = 112.0)

.

speed_racer <- function(v_in = NULL, density = NULL, Cd = NULL, d_rotor = NULL) {
  scenario <<- data.frame(v_in = paste(v_in, "m/s"), density = paste(density, "kg/m^3"), 
                          Cd = Cd, d_rotor = paste(d_rotor, "m"), 
                          A_rotor = paste(as.numeric(pi/4*(as.numeric(d_rotor)^2)), "m^2"))
}

speed_racer(v_in = 2.0, density = 1.2, Cd = 0.00482, d_rotor = 112.0)