R ggvis單個數據幀的多個圖

Question

我查過了，所以請原諒我，如果我失去了一些東西。

假設包含姓名，日期，卡路里，熱量食物是那個人的那一天消耗的卡路里總數數據幀。

Name Date Calories 
Amy  1/1/01 1500 
Amy  1/2/01 1600 
Amy  ...  ... 
Sue  1/1/01 1450 
Sue  1/1/02 1500 
Sue  ...  ... 
Jim  ...  ... 

我想要做的是使用ggvis來繪製每個人（名稱）的卡路里。 我知道我可以使用dplyr的group_by，並將它放在一張圖上，但那樣太忙了。而且我知道我可以使用dplyr的過濾器並過濾掉每個人，併爲每個人製作圖表，但這並不能縮放。

有沒有辦法有ggvis吐出的卡路里每天自動每個人的陰謀？

請注意，我試圖創造一個像下面的函數：

makeCharts <- function(myName){ 
    myTbl %>% filter(Name == myName) %>% ggvis(~Date, ~Calories) 
} 

它的偉大工程，當你手動調用它：

makeCharts("Amy") 

但是，當你通過sapply叫它：

sapply(levels(myTbl$Name), makeCharts) 

輸出看起來是這樣的：

  Amy Sue Jim John Sally Frank Sandy etc...  
marks  List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 
data  List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 
props  List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 List,1 
reactives List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 
scales  List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 
axes  List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 
legends List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 
controls List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 
connectors List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 
handlers List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 
options List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 List,0 
cur_data ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  ?  
cur_props List,2 List,2 List,2 List,2 List,2 List,2 List,2 List,2 List,2 List,2 List,2 List,2 List,2 List,2 List,2 
cur_vis NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL 

Answer 1

一種選擇是使用do。從dplyr的do功能可用於返回對象這樣的功能，讓您輕鬆做一些分組變量的每個級別獨立的情節。

爲您簡單的例子，你只需要與期望的情節，但與數據集作爲唯一的參數編輯您的功能。

makeCharts = function(dat) { 
    dat %>% ggvis(~Date, ~Calories) 
} 

然後對您的數據集進行分組，並通過do對每組進行繪圖。 .指的是每個組的數據集。我將輸出列命名爲plots。

allplots = myTbl %>% 
    group_by(Name) %>% 
    do(plots = makeCharts(.)) 

最終的目標是這樣的：

Source: local data frame [2 x 2] 
Groups: <by row> 

    Name  plots 
1 Amy <S3:ggvis> 
2 Sue <S3:ggvis> 

要打印的所有地塊的繪圖窗口一排，你只需要運行allplots$plots。您可以通過例如allplots$plots[[1]]來提取一個圖。

編輯

您可以通過.參照數據集內do使用任何從數據集。例如，如果你想與組名添加標題像this answer展示瞭如何做，你可以做一個新的功能與第二個參數，包括這個：

makeCharts2 = function(dat, group) { 
    dat %>% ggvis(~Date, ~Calories) %>% 
      add_axis("x", title = "Date") %>% 
      add_axis("x", orient = "top", ticks = 0, title = paste("Plot for", group), 
         properties = axis_props(
           axis = list(stroke = "white"), 
           labels = list(fontSize = 0))) 
} 

然後，只需添加組名稱爲函數的第二個參數。一種方法是通過unique。

allplots2 = myTbl %>% 
    group_by(Name) %>% 
    do(plots = makeCharts2(., unique(.$Name)))