Passing arguments to ggplot and facet_grid - r

Question

I need some help with these lines of code.
My data set:
> str(data.tidy)
Classes ‘tbl_df’, ‘tbl’ and 'data.frame': 9480 obs. of 11 variables:
$ Country.Name : Factor w/ 248 levels "Afghanistan",..: 234 12 13 20 22 31 17 16 25 28 ...
$ Country.Code : Factor w/ 248 levels "ABW","AFG","AGO",..: 7 12 13 16 17 18 19 21 27 28 ...
$ Year : Factor w/ 56 levels "1960","1961",..: 1 1 1 1 1 1 1 1 1 1 ...
$ InfantMortality : num 137.3 20.3 37.3 29.5 186.9 ...
$ AdolFertilityRate: num 176.9 44.8 48.4 27.1 85.8 ...
$ FertilityRate : num 6.93 3.45 2.69 2.54 6.28 ...
$ LifeExpectancy : num 52.2 70.8 68.6 69.7 37.3 ...
$ TotalUnemp : num NA NA NA NA NA NA NA NA NA NA ...
$ TotalPop : num 92612 10276477 7047539 9153489 2431620 ...
$ Region : Factor w/ 8 levels "","East Asia & Pacific",..: 5 2 3 3 8 8 7 5 4 4 ...
$ IncomeGroup : Factor w/ 6 levels "","High income: nonOECD",..: 2 3 3 3 4 4 5 2 5 6 ...
Reference code that I want to 'functionize':
ggplot(data.tidy,aes(as.numeric(as.character(Year)),y=InfantMortality))+
geom_line(aes(color=Country.Name))+
facet_grid(.~IncomeGroup)+
theme(legend.position="none")+
theme(strip.text.x = element_text(size = 7))+
labs(x='Year', title='Change in mortality rate over time')+
geom_smooth(color='black')
I want to replace data.tidy, InfantMortality, IncomeGroup and title in the example above.
Here was my attempt at the code:
facetedlineplot <- function(df,y,facet,title){
ggplot(df,aes(as.numeric(as.character(Year)),y=y))+
geom_line(aes(color=Country.Name))+
facet_grid(.~facet)+
theme(legend.position="none")+
theme(strip.text.x = element_text(size = 7))+
labs(x='Year',title=title)+
geom_smooth(color='black')
}
The error:
> facetedlineplot(data.tidy,y = 'InfantMortality',facet = 'IncomeGroup',title = 'Title goes here')
Error in layout_base(data, cols, drop = drop) :
At least one layer must contain all variables used for facetting
I have tried aes_string, but I couldn't get it to work. What does the error mean? How can I work around this issue?
Update:
I have some code that partially works now, using reformulate()
facetedlineplot <- function(df,y,facet,title){
year <- as.numeric(as.character(df$Year))
ggplot(df,aes(x=year,y=y))+
geom_line(aes(color=Country.Name))+
facet_grid(paste('.~',reformulate(facet)))+
theme(legend.position="none")+
theme(strip.text.x = element_text(size = 7))+
labs(x='Year',title=title)+
geom_smooth(color='black')
}
> facetedlineplot(data.tidy,y = 'InfantMortality', facet = 'IncomeGroup', title = 'Title goes here')
Warning message:
Computation failed in `stat_smooth()`:
x has insufficient unique values to support 10 knots: reduce k.
>
Still, an incorrect plot>
Thank you in advance,
Rahul

Answer 1

I have the solution. Three steps worked for me:
- Change datatype of the Year variable in data.tidy from factor to numeric.
- Use aes_string for the ggplot argument
- For facet_grid(), many things worked:
Use as.formula() to pass '~IncomeGroup'
Just pass '~IncomeGroup' directly to facet_grid()
Final code:
facetedlineplot <- function(df,y,facet,title){
ggplot(df,aes_string(x = 'Year', y = y))+
geom_line(aes(color=Country.Name))+
facet_grid(facet)+
theme(legend.position="none")+
theme(strip.text.x = element_text(size = 9))+
labs(x='Year',title=title)+
geom_smooth(color='black')
}
d <- data.tidy
d$Year <- as.numeric(as.character(d$Year))
facetedlineplot(d,'InfantMortality','~IncomeGroup','Title')