用可选参数在R中编写ggplot函数

本文介绍了用可选参数在R中编写ggplot函数的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我有一系列ggplot图表，我正在重复一些小的变化。我想将这些带有选项的qplots包含到一个函数中，以避免代码中的重复。 我的问题是，对于我使用的一些图+ facet_wrap（）选项，但对于其他人我不是。即我需要facet wrap作为可选参数。当它包含时，代码需要使用facets参数中提供的变量调用+ facet_wrap（）。所以理想情况下，我的函数看起来像这样，facet是一个可选的参数： $ qhist（变量，df，标题，构面） 我试着用Google搜索如何添加可选参数，并且他们建议传递一个默认值或者使用带有missing（）函数的if循环。我还没有得到任何工作。 下面是我写的函数，也包含可选的facets参数的所需功能。 $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $' df，geom =直方图，binwidth = 2000， xlab =薪水，ylab =Noms）+ theme_bw（）+ scale_x_continuous（限制= c（40000,250000 ）， break = c（50000,100000,150000,200000,250000）， labels = c（50k，100k，150k，200k，250k）） + opts（title = heading，plot.title = theme_text（face =bold， size = 14），strip.text.x = theme_text（size = 10，face ='bold'） ）＃如果提供facets参数，则添加以下内容，否则不要添加此代码 + facet_wrap（〜facets） 解决方案设置默认的方式如下所示： testFunction< - function（requiredParam，optionalParam = TRUE，alsoOptional = 123）{ print（requiredParam） if（optionalParam == TRUE）print（you保留optionalParam的默认值） paste（也用于您输入的可选项，也可选）} EDIT * 哦，好的...所以我想我有更好地了解你在问什么。它看起来像你不知道如何将可选的方面带入ggplot对象。如何： qhist< - function（variable，df，heading，facets = NULL）{d< ; - qplot（variable，data = df，geom =histogram，binwidth = 2000， xlab =Salary，ylab =Noms）+ theme_bw（）+ scale_x_continuous （限额= c（40000,250000），中断= c（50000,100000,150000,200000,250000），标签= c（50k，100k，150k， （标题=标题，plot.title = theme_text（face =bold， size = 14），strip.text.x = theme_text（size = 200k，250k））+ opts 10，face ='bold'））＃如果提供facets参数，则添加以下内容，否则不要添加此代码 if（is.null（facets）== FALSE）d d return（d）} 我还没有测试过这个代码。但总体思路是facet_wrap需要一个公式，所以如果facet作为字符串传递，你可以使用 as.formula（）来构建公式，然后添加它到情节对象。 如果我这样做，我会让该函数接受一个可选的构面公式，然后将该构面公式直接传递到 facet_wrap 。这将消除 as.formula（）调用将文本转换为公式的需要。 I have a series of ggplot graphs that I'm repeating with a few small variations. I would like to wrap these qplots with their options into a function to avoid a lot of repetition in the code.My problem is that for some of the graphs I am using the + facet_wrap() option, but for others I am not. I.e. I need the facet wrap to be an optional argument. When it is included the code needs to call the +facet_wrap() with the variable supplied in the facets argument.So ideally my function would look like this, with facets being an optional argument:$ qhist(variable, df, heading, facets)I have tried googling how to add optional arguments and they suggest either passing a default value or using an if loop with the missing() function. I haven't been able to get either to work.Here is the function that I have written, with the desired functionality of the optional facets argument included too. $ qhist <- function(variable, df, heading, facets) { qplot(variable, data = df, geom = "histogram", binwidth = 2000, xlab = "Salary", ylab = "Noms") + theme_bw() + scale_x_continuous(limits=c(40000,250000), breaks=c(50000,100000,150000,200000,250000), labels=c("50k","100k","150k","200k","250k")) + opts(title = heading, plot.title = theme_text(face = "bold", size = 14), strip.text.x = theme_text(size = 10, face = 'bold')) # If facets argument supplied add the following, else do not add this code + facet_wrap(~ facets) 解决方案 the way to set up a default is like this:testFunction <- function( requiredParam, optionalParam=TRUE, alsoOptional=123 ) { print(requiredParam) if (optionalParam==TRUE) print("you kept the default for optionalParam") paste("for alsoOptional you entered", alsoOptional)}*EDIT*Oh, ok... so I think I have a better idea of what you are asking. It looks like you're not sure how to bring the optional facet into the ggplot object. How about this: qhist <- function(variable, df, heading, facets=NULL) { d <- qplot(variable, data = df, geom = "histogram", binwidth = 2000, xlab = "Salary", ylab = "Noms") + theme_bw() + scale_x_continuous(limits=c(40000,250000), breaks=c(50000,100000,150000,200000,250000), labels=c("50k","100k","150k","200k","250k")) + opts(title = heading, plot.title = theme_text(face = "bold", size = 14), strip.text.x = theme_text(size = 10, face = 'bold')) # If facets argument supplied add the following, else do not add this code if (is.null(facets)==FALSE) d <- d + facet_wrap(as.formula(paste("~", facets))) d return(d) }I have not tested this code at all. But the general idea is that the facet_wrap expects a formula, so if the facets are passed as a character string you can build a formula with as.formula() and then add it to the plot object. If I were doing it, I would have the function accept an optional facet formula and then pass that facet formula directly into the facet_wrap. That would negate the need for the as.formula() call to convert the text into a formula. 这篇关于用可选参数在R中编写ggplot函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！