使用ggplot2在循环中创建图 [英] Create plots in a loop using ggplot2

问题描述

我的示例数据集：

<$ p $ （名称= c（john，alex，mike，dennis，alex），
费用= c（ 10，12，15，8，2），
type = c（食物，租金，租金，食物，食物）） b $ b

我想要在单个图表中为每个名称的费用绘制条形图。 alex的情节将如下所示：

  selected.name<  - alex
 df1< - 子集（df，name == selected.name）
 ggplot（data = df1，aes（type，expenses））+ geom_bar（）
  

现在我想要使用一个循环，为df中的每个名称绘制相同的绘图。我试图使用运行上面剧情代码的for循环作为源文件。但我无法将名称变量传递给源文件，以便为每个名称绘制图形。现在我只能从for循环中获得一个图表。

解决方案

回答你的原始问题。使用标准R来做到这一点：

  doPlot = function（sel_name）{
 dum = subset（df，name = = sel_name）
 ggobj = ggplot（data = dum，aes（type，expenses））+ geom_bar（）
 print（ggobj）
 ggsave（sprintf（％s.pdf，sel_name ））
} 
 lapply（unique（df $ name），doPlot）
  

通过这种方式，最终得到大量名为Adam.pdf的pdf文件。然后，您可以使用pdftk（pdf工具包）将文件一起捕获到一个文档中。我仍然更喜欢使用例如更好的解决方案。小平面或不同类型的情节。

使用facetting不会更好吗？给出你的例子，代码将是：

pre $ g $ pggplot（data = df，aes（type，expenses））+
geom_bar（）+ facet_wrap（〜name）

导致下面的情节：

也许对于250个名称和更多变量，这可能是一个问题。但是我仍然会考虑面向。

I have to generate 250 plots with the same view.

My example data set:

df <- data.frame(name = c("john","alex","mike","dennis","alex"),
             expenses = c("10","12","15","8","2"),
             type = c("food","rent","rent","food","food"))

I would like bar plots with the expenses for every name in a single plot. The plot for "alex" will look like:

selected.name <- "alex"
df1 <- subset(df, name == selected.name)
ggplot(data = df1, aes(type, expenses)) + geom_bar()

Now I want to use a loop that plots the same plot for every name in the df. I have tried to use a for loop that runs the plot code above as a source file. But I can't pass the name variable to the source file so that it plots the graph for every name. Now I only get one graph out of the for loop.

解决方案

To answer your orignal question. To do this using standard R:

doPlot = function(sel_name) {
   dum = subset(df, name == sel_name)
   ggobj = ggplot(data = dum, aes(type, expenses)) + geom_bar()
   print(ggobj)
   ggsave(sprintf("%s.pdf", sel_name))
}
lapply(unique(df$name), doPlot)

In this way you end up with a large number of pdf files called Adam.pdf etc. You could then use pdftk (pdf tool kit) to cat the files together in one document. I would still prefer, a better solution using e.g. facetting or a different type of plot.

Wouldn't it be much better to use facetting? Given your example the code would be:

ggplot(data = df, aes(type, expenses)) + 
   geom_bar() + facet_wrap(~name)

which leads to the following plot:

Maybe for 250 names and more variables, this might be a problem. But I'd look at facetting nonetheless.

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