R help - Aug 2017 - ggplot's aes_ doesn't work as expected for x=factor()

I'm learning how to use ggplot in a programming approach where I supply
variable names on the fly.  Using aes_ doesn't work as I expected when x =
factor(x).  Is this a bug or am I not understanding something?

# toy dataset
df <- data.frame(LogicalVar = c(FALSE, TRUE, FALSE, TRUE, FALSE, TRUE),
                 Var1 = c(0.01, 0.01, 1, 1, 30, 30),
                 pct1 = c(12, 88, 60, 40, 93, 7),
                 Var2 = c(2, 2, 4, 4, 8, 8),
                 pct2 = c(43, 57, 10, 90, 50, 50)
                )
varnames <- names(df)
# using aes()--this works
ggplot(df, aes(x=factor(Var1), y=pct1, fill=LogicalVar)) +
geom_bar(stat="identity")  # works

# using aes_() works in this instance
ggplot(df, aes_(x=as.name(varnames[2]), y=as.name(varnames[3]),
fill=as.name(varnames[1]))) + geom_bar(stat="identity")  # works

# it doesn't work here, where only change is using x=factor()
ggplot(df, aes_(x=factor(as.name(varnames[2])), y=as.name(varnames[3]),
fill=as.name(varnames[1]))) + geom_bar(stat="identity") # doesn't
work
Error in unique.default(x, nmax = nmax) :
  unique() applies only to vectors

# aes_ does work if I make the x variable a factor ahead of time
df2 <- df
df2$Var1 <- as.factor(df2$Var1)
ggplot(df2, aes_(x=as.name(varnames[2]), y=as.name(varnames[3]),
fill=as.name(varnames[1]))) + geom_bar(stat="identity") # works

Regards,
Scott Waichler
Pacific Northwest National Laboratory
Richland, WA, USA

Hi

The error does not come from ggplot but from factor function.

factor(as.name(varnames[2]))
Error in unique.default(x, nmax = nmax) :
  unique() applies only to vectors
>
If you does not intend to use facet it is easier to use aes with column numbers
and annotate from names

like
ggplot(df, aes(x=factor(df[,2]), y=df[,3], fill=df[,1])) +
geom_bar(stat="identity")+xlab(varnames[2])

Cheers
Petr


> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of
Waichler,
> Scott R
> Sent: Monday, August 14, 2017 1:38 AM
> To: R. Help <r-help at r-project.org>
> Subject: [R] ggplot's aes_ doesn't work as expected for x=factor()
>
> I'm learning how to use ggplot in a programming approach where I supply
> variable names on the fly.  Using aes_ doesn't work as I expected when
x > factor(x).  Is this a bug or am I not understanding something?
>
> # toy dataset
> df <- data.frame(LogicalVar = c(FALSE, TRUE, FALSE, TRUE, FALSE, TRUE),
>                  Var1 = c(0.01, 0.01, 1, 1, 30, 30),
>                  pct1 = c(12, 88, 60, 40, 93, 7),
>                  Var2 = c(2, 2, 4, 4, 8, 8),
>                  pct2 = c(43, 57, 10, 90, 50, 50)
>                 )
> varnames <- names(df)
> # using aes()--this works
> ggplot(df, aes(x=factor(Var1), y=pct1, fill=LogicalVar)) +
> geom_bar(stat="identity")  # works
>
> # using aes_() works in this instance
> ggplot(df, aes_(x=as.name(varnames[2]), y=as.name(varnames[3]),
> fill=as.name(varnames[1]))) + geom_bar(stat="identity")  # works
>
> # it doesn't work here, where only change is using x=factor()
> ggplot(df, aes_(x=factor(as.name(varnames[2])), y=as.name(varnames[3]),
> fill=as.name(varnames[1]))) + geom_bar(stat="identity") #
doesn't work
> Error in unique.default(x, nmax = nmax) :
>   unique() applies only to vectors
>
> # aes_ does work if I make the x variable a factor ahead of time
> df2 <- df
> df2$Var1 <- as.factor(df2$Var1)
> ggplot(df2, aes_(x=as.name(varnames[2]), y=as.name(varnames[3]),
> fill=as.name(varnames[1]))) + geom_bar(stat="identity") # works
>
> Regards,
> Scott Waichler
> Pacific Northwest National Laboratory
> Richland, WA, USA
>
> ______________________________________________
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