如果在其他列中满足条件，则将值附加到向量答案

【问题标题】：Append value to vector if condition met in other column如果在其他列中满足条件，则将值附加到向量
【发布时间】：2020-09-21 12:10:54
【问题描述】：

我正在循环几个数据帧，我正在尝试根据 df["TEST"] 中的值填充一个向量。

对于数据帧的每一行——除了最后两行——如果 df["TEST"] 中的值为 1，我想将 df["HOD"] 中的相应值附加到我的向量 v。

这是我正在循环的数据帧的结构：

df <- structure(list(GAME = structure(c("Tottenham/Crystal Palace", 
"Valencia/Leganes", "Atl. Madrid/Celta Vigo", "Granada CF/Barcelona", 
"Napoli/Cagliari", "Brescia/Juventus", "CASH", "TOTAL"), .Names = c(NA, 
NA, NA, NA, NA, NA, "GAME", "GAME")), WEIGHT = c(2.23823589057186, 
2.61685996579251, 2.63527504587693, 0.457669317949777, 2.64922876342808, 
11.1833333333333, 78.2193976830475, 100), RECO = structure(c("Tottenham", 
"Valencia", "Atl. Madrid", "Granada CF", "Napoli", "Juventus", 
"/", "/"), .Names = c(NA, NA, NA, NA, NA, NA, "RECO", "RECO")), 
    SIDE = structure(c("back", "back", "back", "back", "back", 
    "back", "/", "/"), .Names = c(NA, NA, NA, NA, NA, NA, "SIDE", 
    "SIDE")), LEAGUE = structure(c("Premier League", "Liga", 
    "Liga", "Liga", "Serie A", "Serie A", "/", "/"), .Names = c(NA, 
    NA, NA, NA, NA, NA, "LEAGUE", "LEAGUE")), IDGAME = structure(c("G233051", 
    "G233135", "G233113", "G233112", "G233175", "G233158", "/", 
    "/"), .Names = c(NA, NA, NA, NA, NA, NA, "IDGAME", "IDGAME"
    )), TEST = structure(c("1", "0", "0", "1", "0", "1", "1", 
    "1"), .Names = c(NA, NA, NA, NA, NA, NA, "TEST", "TEST")), 
    HOD = structure(c("1.3", "1.5", "1.36", "8", "1.25", "1.36", 
    "1", "1"), .Names = c(NA, NA, NA, NA, NA, NA, "HOD", "HOD"
    )), AMOUNT = c(0.283340944091571, 0.331271416201643, 0.333602603096921, 
    0.0579369034228574, 0.335369020801678, 1.41571147085297, 
    1, 1), LONG = c(-0.283340944091571, -0.331271416201643, -0.333602603096921, 
    -0.0579369034228574, -0.335369020801678, -1.41571147085297, 
    93.452071771034, 96.2093041295016), SHORT = c(0, 0, 0, 0, 
    0, 0, 1, 1), CTR = c(0.368343227319042, 0, 0, 0.463495227382859, 
    0, 1.92536760036004, 93.452071771034, 96.2092778260959)), row.names = c(NA, 
-8L), class = "data.frame")

以下是我尝试过的。我也尝试了 ifelse 但找不到解决方法。

v <-vector()
  for(j in seq(38)){  
    n <-paste0("FWKD",j)
    if(exists(n)){
      df<-get(n)
      apply(df, 1, function(x){
        if(df[[x,"TEST"]] ==1){
          v <- append(v, df[[x,"HOD"]])
        }
      })
    }
  }
  assign("OUTPUT1",as.data.frame(v))

感谢您的帮助

【问题讨论】：

标签： r

【解决方案1】：

你可以这样做：

#Remove last 2 rows
tmp <- head(df, -2)
#Get the corresponding value of HOD where TEST = 1
v <- as.numeric(tmp$HOD[tmp$TEST == 1])
v
#[1] 1.30 8.00 1.36

【讨论】：

【解决方案2】：

以下代码可能有效，我假设您有一个数据框列表，因为您说您正在尝试遍历其中的几个。最后，使用do.call 函数，您将在每个data.frame 上拥有一个包含所有HOD 值的向量。不过，我不能完全确定这个问题是否是你想要的。

get_hod <- function(df){
    df = df[1:(nrow(df) - 2), ]
    output <- df[df$TEST == 1, "HOD"] 
     
    return(output)
}

## df_list is a list of data.frame objects
df_hod <- lapply(df_list, get_hod) # using lapply instead of for loop 
my_vector <- do.call(c, df_hod)

【讨论】：