如何在R中打印無標題和NA值的行

我有一個名爲decision_tree的數據框。我需要用條件從數據框中打印一行。例如：Student_id == 100.如何在R中打印無標題和NA值的行

selected_row <- filter(decision_tree, Student_id=100)

但是我收到了一些奇怪的錯誤。

Error: Each variable must be a 1d atomic vector or list. 
Problem variables: 'Student_id' 

decision_tree <- plyr::ldply(Recommendations, rbind) 
decision_tree$Student_id <- select(r_df, Student_id) 
colnames(decision_tree) <- c("Recommended Course 1","Recommended Course 2","Recommended Course 3","Recommended Course 4","Recommended Course 5","Student_id")

數據幀看起來像：

最後場是數字和其它字段是與7級或9的水平的因素。

即使我將colnames設置爲NULL。最後一列將有一個Student_id。前5列名稱將從1到5

結構（列表（Recommended Course 1 =結構（c（NA，NA，NA， 5L，NA，NA，NA，NA，8L，2L），。標籤= c（「p_F20BC」，「p_F20DL」，「p_F20DP」，「p_F20DV」，「p_F20GP」，「p_F20MA」，「p_F20MC」，「p_F20RO」，「p_F20RS」），class =「factor」），Recommended Course 2 =結構（c（NA， NA，9L，NA，NA，NA，2L，7L），標籤= c（「p_F20BC」，「p_F20DL」，「p_F20DP」，「p_F20DV」，「p_F20GP 「，」p_F20MA「，」p_F20MC「，」p_F20RO「，」p_F20RS「），class =」factor「），Recommended Course 3 = structure（c（NA， NA，NA，NA，NA，NA，NA，NA， 1L，3L），。標籤= c（「p_F20BC」，「p_F20DL」，「p_F20DP 」，「p_F20GP」，「p_F20MC」，「p_F20RO」），類= 「因子」）， Recommended Course 4 =結構（C（NA_integer_，NA_integer_， NA_integer_，NA_integer_，NA_integer_，NA_integer_，NA_integer_， NA_integer_，NA_integer_，NA_integer_ ），標籤=「p_F20BC」，class =「factor」）， Student_id = structure（list（Student_id = c（55L，68L，70L， 99L，100L，101L，103L，105L，106L，107L） .Names =「Student_id」，row.names = c（NA， 10L），class =「data.frame」）），.Names = c（「推薦課程1」，「推薦課程2」，「 3「，」Recommended Course 4「，」Student_id「），row.names = c（NA，10L），class =」data.frame「）

來源

2017-04-05 Murlidhar Fichadia

你能不能做到？：selected_row < - 構造判定[其中（判定樹[ 「student_id數據」] == 100）] –

@EvanFriedland沒錯，就是工作。但它也會打印帶有na值的標題和列。如何像列表一樣打印？只是單元格的價值。一個在另一個下方 –

你可以粘貼你想要的輸出嗎？我在這裏猜測。 –

編輯：您的輸入數據與您的圖像不同。以下代碼會生成字符（0）的結果，因爲存在沒有課程建議的行。在評論中讓我知道你想如何處理這些。

decision_tree <- structure(list("Recommended Course 1" = structure(c(NA, NA, NA, 5L, NA, NA, NA, NA, 8L, 2L), .Label = c("p_F20BC", "p_F20DL", "p_F20DP", "p_F20DV", "p_F20GP", "p_F20MA", "p_F20MC", "p_F20RO", "p_F20RS"), class = "factor"), "Recommended Course 2" = structure(c(NA, NA, NA, 9L, NA, NA, NA, NA, 2L, 7L), .Label = c("p_F20BC", "p_F20DL", "p_F20DP", "p_F20DV", "p_F20GP", "p_F20MA", "p_F20MC", "p_F20RO", "p_F20RS"), class = "factor"), "Recommended Course 3" = structure(c(NA, NA, NA, NA, NA, NA, NA, NA, 1L, 3L), .Label = c("p_F20BC", "p_F20DL", "p_F20DP", "p_F20GP", "p_F20MC", "p_F20RO"), class = "factor"), "Recommended Course 4" = structure(c(NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_, NA_integer_), .Label = "p_F20BC", class = "factor"), Student_id = structure(list(Student_id = c(55L, 68L, 70L, 99L, 100L, 101L, 103L, 105L, 106L, 107L)), .Names = "Student_id", row.names = c(NA, 10L), class = "data.frame")), .Names = c("Recommended Course 1", "Recommended Course 2", "Recommended Course 3", "Recommended Course 4", "Student_id"), row.names = c(NA, 10L), class = "data.frame") 


recommend <- function(StudentID){ 
    courses <- grep("Course", colnames(decision_tree)) 
    id <- grep("id", colnames(decision_tree)) 
    rows <- which(decision_tree[,id] == StudentID) 
    x <- decision_tree[rows,courses][!is.na(decision_tree[rows,courses])] 
    if(length(x) == 0) { 
    paste("No course to recommend") 
    } else { 
    x 
    } 
} 
recommend(99) 
    "p_F20GP" "p_F20RS" 

for(i in 1:nrow(decision_tree)){ 
    print(recommend(decision_tree$Student_id[i,])) 
} 
[1] "No course to recommend" 
[1] "No course to recommend" 
[1] "No course to recommend" 
[1] "p_F20GP" "p_F20RS" 
[1] "No course to recommend" 
[1] "No course to recommend" 
[1] "No course to recommend" 
[1] "No course to recommend" 
[1] "p_F20RO" "p_F20DL" "p_F20BC" 
[1] "p_F20DL" "p_F20MC" "p_F20DP"

來源

2017-04-06 00:03:22

它不會工作，我得到邏輯（0）作爲輸出。因爲這段代碼不會自行工作。問題是data.frame不能正常工作。數據$ student_id數據。Student_id不會工作行< - 哪個（data $ Student_id.Student_id == StudentID） –

您可以發佈dput（decision_tree [1:10，]）的結果嗎？ –

我在我的問題中添加了輸出。抱歉雜亂的輸出。 –

如何在R中打印無標題和NA值的行

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