ggplot in r：自動設置線型

Question

我想在ggplot調用中自動設置線型，我將在for循環中運行 。數據在var2變量中有大約20個值，我通過循環訪問Eurostoxx（索引）和另一個值來一次繪製圖表。

這裏是第一行：

 Date value    var1     var2 

     2011-09-30 20.67 Return on Equity    Eurostoxx 

我想具有Eurostoxx如每一個曲線圖中的實線（它是混亂 讀者時它切換）。

我知道如何設置手動線型：

gp<- gp + scale_linetype_manual("",values=c("Eurostoxx"="dotted","Automobiles and Parts"="solid")) 

，但我試圖在data.frame（規模$ output_breaks這

secnam<-unique(g$var2)[!unique(g$var2)%in%"Eurostoxx"] 
secnam 

#"Automobiles and Parts" 

gp<- gp + scale_linetype_manual("",values=c("Eurostoxx"="dotted",secnam="solid")) 

自動運行到錯誤

錯誤（），I（scale $ labels（）））： 行名包含缺失值

下面的代碼重現了這個問題。

gfull<-structure(list(Date = structure(c(15247, 15278, 15308, 15338, 
15247, 15278, 15308, 15338, 15247, 15278, 15308, 15338, 15247, 
15278, 15308, 15338, 15247, 15278, 15308, 15338, 15247, 15278, 
15308, 15338), class = "Date"), value = c(20.67, 19.81, 19.81, 
19.92, 1.2966, 1.4054, 1.3744, 1.3828, 16.36, 16.58, 16.86, 16.7, 
0.8263, 0.9167, 0.8642, 0.8197, 13.32, 12.82, 12.59, 12.55, 1.1672, 
1.1721, 1.1643, 1.1509), var1 = c("Return on Equity", "Return on Equity", 
"Return on Equity", "Return on Equity", "Price to Book", "Price to Book", 
"Price to Book", "Price to Book", "Return on Equity", "Return on Equity", 
"Return on Equity", "Return on Equity", "Price to Book", "Price to Book", 
"Price to Book", "Price to Book", "Return on Equity", "Return on Equity", 
"Return on Equity", "Return on Equity", "Price to Book", "Price to Book", 
"Price to Book", "Price to Book"), var2 = c("Eurostoxx", "Eurostoxx", 
"Eurostoxx", "Eurostoxx", "Eurostoxx", "Eurostoxx", "Eurostoxx", 
"Eurostoxx", "Automobiles and Parts", "Automobiles and Parts", 
"Automobiles and Parts", "Automobiles and Parts", "Automobiles and Parts", 
"Automobiles and Parts", "Automobiles and Parts", "Automobiles and Parts", 
"Utilities", "Utilities", "Utilities", "Utilities", "Utilities", 
"Utilities", "Utilities", "Utilities")), .Names = c("Date", "value", 
"var1", "var2"), row.names = c(71L, 72L, 73L, 74L, 4511L, 4512L, 
4513L, 4514L, 145L, 146L, 147L, 148L, 4585L, 4586L, 4587L, 4588L, 
1477L, 1478L, 1479L, 1480L, 5917L, 5918L, 5919L, 5920L), class = "data.frame") 

代碼：

g<-gfull 
g<-subset(gfull, var2 %in% c("Eurostoxx","Automobiles and Parts")) 

    gp <- ggplot(g, aes(Date, value,group=var2,lty=var2)) 
    gp <-gp + facet_grid(var1~., scales="free") 
    gp<- gp + geom_line() 

#EUROSTOXX is dotted 

g<-gfull 
g<-subset(g,var2%in%c("Eurostoxx","Utilities")) 
    gp <- ggplot(g, aes(Date, value,group=var2,lty=var2)) 
    gp <-gp + facet_grid(var1~., scales="free") 
    gp<- gp + geom_line() 

#EUROSTOXX is solid 

    secnam<-unique(g$var2)[!unique(g$var2)%in%"Eurostoxx"] 
    gp<- gp + scale_linetype_manual("",values=c("Eurostoxx"="dotted",secnam="solid")) 
    gp 

    #Error in data.frame(scale$output_breaks(), I(scale$labels())) : 
    #row names contain missing values 

Answer 1

有可能做你正在試圖完成的更優雅的方式，而是以解決特定的問題，讓我們來看看究竟c("Eurostoxx"="dotted",secnam="solid")是什麼：

> c("Eurostoxx"="dotted",secnam="solid") 
Eurostoxx secnam 
"dotted" "solid" 

請注意，您試圖用值在secnam中命名元素「固體」，但R不起作用辦法。 （至少，沒有鑽研使用eval，parse，substitute之類的，但是這複雜得多，我們需要的。）

相反，剛剛創建的線型載體中，然後直接修改名稱，使用names功能：

> l <- c("dotted","solid") 
> names(l) <- c("Eurostoxx",unique(g$var2)[!unique(g$var2)%in%"Eurostoxx"]) 
> l 
Eurostoxx Utilities 
"dotted" "solid" 

，然後將載體l傳遞給scale_linetype_manual中的值參數。