R - 忽略空？

Question

要声明：我正在寻找的所有东西都像if语句，如果数据框没有行，它会以某种方式忽略整个add_trace函数。

我有下列R-代码：

g <- plot_ly(df, x = ~Day) %>% 
    add_trace(data=df[which(df$FcNum==1),], y = ~ProjAmount, name = 'Line 1', hoverinfo = "text", text = ~paste('Projected Amt: ', round(ProjAmount,2)), mode = 'lines', width = 1, connectgaps = "false") %>% 
    add_trace(data=df[which(df$FcNum==2),], y = ~ProjAmount, name = 'Line 2', hoverinfo = "text", text = ~paste('Projected Amt: ', round(ProjAmount,2)), mode = 'lines', width = 1, connectgaps = "false") 

我的数据帧是这样的：

Day  Amount ProjAmt  FcNum  
1   10.4  55   1   
1   10.4  37   2   
2   22.1  55   1   
2   22.1  37   2   
3   43.5  55   1   
3   43.5  37   2   
4   24.1  55   1   
4   24.1  55   2   
...   ...  ... 
34   37.8  75   1   
34   37.8  99   2   
35   12.8  75   1   
35   12.8  99   2   

我使用的可视化工具失败的脚本时，我就FcNum过滤（这样当我添加一个过滤器的视觉，并说“只给我价值，其中FcNum是1”）。可视化失败，因为FcNum == 2中不再有值，并且它返回以下错误消息：“错误：变量必须是长度为1或1”。

（有啥幕后发生的事情是它的过滤数据帧到这个样子，注意到在FcNum列中的值：

Day  Amount ProjAmt  FcNum  
1   10.4  55   1   
2   22.1  55   1   
3   43.5  55   1   
4   24.1  55   1   
...   ...  ... 
34   37.8  75   1   
35   12.8  75   1 

换句话说，当代码3号线没有返回值，因为它要求每个变量的值都是1或1，所以无法显示图形。

是否有一个函数，可能在基数R中允许我在数据框为空时设置替代值？

我试过了像

add_trace(data=na.omit(df[which(df$FcNum==2),]), y = ~ProjAmount, name = 'Line 2', hoverinfo = "text", text = ~paste('Projected Amt: ', round(ProjAmount,2)), mode = 'lines', width = 1, connectgaps = "false") 

....但那并没有工作。

Answer 1

下面的代码似乎工作正常（没有错误或警告）。我添加了type = "scatter"并删除了width = 1。

# First 8 rows of your data 
df <- structure(list(Day = c(1L, 1L, 2L, 2L, 3L, 3L, 4L, 4L), Amount = c(10.4, 
10.4, 22.1, 22.1, 43.5, 43.5, 24.1, 24.1), ProjAmount = c(55L, 
37L, 55L, 37L, 55L, 37L, 55L, 55L), FcNum = c(1L, 2L, 1L, 2L, 
1L, 2L, 1L, 2L)), .Names = c("Day", "Amount", "ProjAmount", "FcNum" 
), class = "data.frame", row.names = c(NA, -8L)) 

library(plotly) 

plot_ly(df, x = ~ Day) %>% 
    add_trace(
    data = df[which(df$FcNum == 1), ], 
    type = "scatter", # new line 
    y = ~ ProjAmount, 
    name = 'Line 1', 
    hoverinfo = "text", 
    text = ~ paste('Projected Amt: ', round(ProjAmount, 2)), 
    mode = 'lines', 
    # width = 1, 
    connectgaps = "false" 
) %>% 
    add_trace(
    data = df[which(df$FcNum == 2), ], 
    type = "scatter", # new line 
    y = ~ ProjAmount, 
    name = 'Line 2', 
    hoverinfo = "text", 
    text = ~ paste('Projected Amt: ', round(ProjAmount, 2)), 
    mode = 'lines', 
    # width = 1, 
    connectgaps = "false" 
)