CODEWITHSUNDEEP
rggplot2
user11634
user11634

Reputation: 306

ggplot2 in function: non-numeric argument to binary operator

The following works well (I get the right plots):

library(ggplot2)

myfunc <- function(x)
{
  n = length(x)
  return(sqrt(x)+rnorm(n,0,0.05))
}

myplot1 <- function(df,x,color)
{
  df$y <- myfunc(df[[x]])
  p  <- geom_point(data=df,
                   aes_string(x=x,y="y"),
                   colour=color) 
  return(p)
}

myplot2 <- function(df,x,color)
{
  df$y <- myfunc(df[[x]])
  p  <- geom_smooth(data=df,
                   aes_string(x=x,y="y"),
                   colour=color,
                   method="lm") 
  return(p)
}

n <- 100
df <- data.frame( X1 = runif(n,0,1),
                  X2 = rnorm(n,0.5,0.01))
p <- ggplot()
p <- p + myplot1(df,"X1","black") + myplot2(df,"X1","black")
p <- p + myplot1(df,"X2","blue")  + myplot2(df,"X2","blue")
p + theme_minimal()

however, if I merge the two functions myplot1 and myplot2 as in

myplot <- function(df,x,color)
{
  df$y <- myfunc(df[[x]])
  p  <- geom_point(data=df,
                   aes_string(x=x,y="y"),
                   colour=color)  +
        geom_smooth(data=df,
                      aes_string(x=x,y="y"),
                      colour=color,
                      method="lm")
  return(p)
}

and so use

p <- ggplot()
p <- p + myplot(df,"X1","black")
p <- p + myplot(df,"X2","blue")
p + theme_minimal()

I get

Error [...] non-numeric argument to binary operator

How can I solve this issue ?

Upvotes: 2

Views: 2754

Answers (1)

IanK
IanK

Reputation: 386

For some reason combining those geoms is causing a problem. You can return them as a list and get it to work:

library(ggplot2)

n <- 100
df <- data.frame( X1 = runif(n,0,1),
                  X2 = rnorm(n,0.5,0.01))

myfunc <- function(x)
{
  n = length(x)
  return(sqrt(x)+rnorm(n,0,0.05))
}

myplot <- function(mydata,x,color)
{
  mydata$y <- myfunc(mydata[[x]])
  p <- geom_point(data = mydata, aes_string(x = x, y = 'y'), color = color)
  q <- geom_smooth(data = mydata, aes_string(x = x, y = 'y'), color = color, method = 'lm')
  return(list(p, q))
}


p <- ggplot()
p <- p + myplot(df,"X1","black")
p <- p + myplot(df,"X2","blue")
p + theme_minimal()

Upvotes: 2

Related Questions