Question

library(tidyverse)
xy <- data.frame(xvar = 1:10, yvar = 1:10)

plotfunc <- function(data, x, y){
  print(
    ggplot(data, aes_(x = substitute(x), y = substitute(y))) + 
      geom_line()
  )
}
plotfunc(xy, xvar, yvar)

上面的功能工作正常。以下功能没有。如何进行如下所示的正确分配？我知道他们实际上并不会做任何事情，但是我无论如何都不会开始正确使用我的语法。

plotfunc <- function(data, x, y){
  rng <- range(substitute(x), na.rm = TRUE)
  rescale <- (substitute(x) - rng[1]) / (rng[2] - rng[1])
  print(
    ggplot(data, aes_(x = substitute(x), y = substitute(y))) + 
      geom_line()
  )
}
plotfunc(xy, xvar, yvar)

Answer 1

您需要在xvar的上下文中评估data.frame：

plotfunc <- function(data, x, y){
  rng <- range(eval(substitute(x),envir = data), na.rm = TRUE)
  rescale <- (eval(substitute(x),envir = data) - rng[1]) / (rng[2] - rng[1])
  print(
    ggplot(data, aes_(x = substitute(x), y = substitute(y))) + 
      geom_line()
  )
}
plotfunc(xy, xvar, yvar)

Answer 2

这里是使用更多tidyverse编程风格的另一种选择：

<?xml version="1.0" encoding="UTF-8"?>
<t:BaseButtonTemplate xmlns="http://xamarin.com/schemas/2014/forms" 
                       xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
                       xmlns:t="clr-namespace:Japanese.Templates" 
                       xmlns:local="clr-namespace:Japanese;assembly=Japanese" 
                       x:Class="Japanese.Templates.Btn" x:Name="this">
    <StackLayout Padding="10"
                 HorizontalOptions="CenterAndExpand" 
                 VerticalOptions="CenterAndExpand" >
        <StackLayout.GestureRecognizers>
            <TapGestureRecognizer Command="{Binding TapCommand, Source={x:Reference this}}" 
                                  CommandParameter="{Binding TapCommandParam, Source={x:Reference this}}" 
                                  NumberOfTapsRequired="1" />
        </StackLayout.GestureRecognizers>
        <Frame CornerRadius="25" 
               BorderColor="{Binding FrameBorderColor, Source={x:Reference this}}"
               BackgroundColor="{Binding FrameBackgroundColor, Source={x:Reference this}}" 
               HorizontalOptions="Center" VerticalOptions="Center" HasShadow="false" Padding="0"
               WidthRequest="50" 
               HeightRequest="50">
                <Label TextColor="{Binding LabelTextColor, Source={x:Reference this}}"
                       Text="{Binding Text, Source={x:Reference this}}" 
                       HorizontalOptions="Center" VerticalOptions="Center" 
                       HorizontalTextAlignment="Center" VerticalTextAlignment="Center"
                       FontFamily="FontAwesome5ProRegular" />
        </Frame>
    </StackLayout>
</t:BaseButtonTemplate>

函数内部的R分配

2 个答案: