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Error: Cannot use `+.gg()` with a single argument.

3 messages · Ana Marija, Richard M. Heiberger, Rui Barradas

Ana Marija
# 
Hello,

I got this error:
Error: Cannot use `+.gg()` with a single argument. Did you
accidentally put + on a new line?

After running this:
data(murders)
library(ggplot2)
library(dplyr)
library(ggplot2)
ggplot(data=murders)

#define the slope of the line
r<-murders %>% summarize(rate=sum(total)/sum(population)*10^6) %>%.$rate
#mamke the plot
murders %>% ggplot(aes(population/10^6,total,label=abb))+
  +geom_abline(intercept = log10(r),lty=2,color="darkgrey")+
  +geom_point(aes(col=region), size=3)+
  +geom_text_repel()+
  +scale_x_log10()+
  +scale_y_log10()+
  +xlab("Populations in millions (log scale)")+
  +ylab("Total number of murders (log scale)")+
  +ggtitle("US Gun Murders in US 2010")+
  +scale_color_discrete(name="Region")+
  +theme_economist()

Is this an issue with my dplyr? Or how I can fix this code in order to work?

Thanks
Ana
Richard M. Heiberger
# 
It is just like the message suggested. You have a + at the end of each line
and
the beginning of the next.  The one at the end is required.  The ones at
the beginning are
causing the error message.

Please put spaces around your assignment arrows.
Difficult to read:  r<-murders
Easy to read:    r <- murders

On Thu, May 7, 2020 at 10:46 PM Ana Marija <sokovic.anamarija at gmail.com>
wrote:

  
  


  


      

    

    

      
      

        


  

        

      Rui Barradas
    

    

      
      #
    

  


  

      
Hello,

Richard's answer solves the problem, I'm writing about details in the 
OP's post.

Ana, your code example is missing some library() calls:

library(ggplot2)
library(ggrepel)
library(ggthemes)
library(dplyr)

# and where to find the data set
data(murders, package = "dslabs")


As for the dplyr pipe, you end it with .$rate to pull only that column's 
value, the following avoids that construct and is, I believe, more 
idiomatic:

#define the slope of the line
r <- murders %>%
   summarize(rate = sum(total)/sum(population)*10^6) %>%
   pull(rate)


Hope this helps,

Rui Barradas


?s 04:27 de 08/05/20, Richard M. Heiberger escreveu: