參數暗示行數與繪制數據幀的行數不同

Question

我有一個看起來像這樣的數據框df

        a    b     c     d
row1    1    2     2     3
row2    2    4     5     9
row3    1    4     4     6

對於每一行，我想在pdf中將直方圖寫入頁面。 我試圖這樣做

for (i in 1:nrow(df)){
    histogram <- ggplot(data=df, aes(x=as.numeric(df[i,]))) +geom_histogram()
    ggsave(filename="output.pdf", plot=histogram)
}

但是，這給了我錯誤arguments imply differing number of rows: 115, 734 。 從這個答案： https : //stackoverflow.com/a/26148043/651779我試圖做

df$id <- rownames(df)
df <- melt(df)
for (i in 1:nrow(df)){
  histogram <- ggplot(data=df, aes(x=as.numeric(df[i,]))) +geom_histogram()
  ggsave(filename="output.pdf", plot=histogram)
}

但這給了我同樣的錯誤，但是arguments imply differing number of rows: 3, 84410不同arguments imply differing number of rows: 3, 84410數arguments imply differing number of rows: 3, 84410

Answer 1

怎么樣：

for (i in 1:nrow(df)) {
  df2 <- data.frame(x = as.numeric(df[i, ]))
  histogram <- ggplot(data = df2, aes(x)) + geom_histogram()
  ggsave(filename = "output.pdf", plot = histogram)
}

Answer 2

我將使用t轉置data.frame，然后像這樣繪制：

#transpose df
df <- data.frame(t(df))

#notice aes_string in order for i to be the name as character
for (i in names(df)){
  histogram <- ggplot(df, aes_string(x=i)) + geom_histogram()
  ggsave(filename="output.pdf", plot=histogram)
}