How can I use the content of a vector as title in ggplot?

Question

I'm trying to use the typed content of a vector as title for a graph. Therefore (i think) i first need to convert the typed content to characters. And here it gets tricky....

I already tried to convert the content to "as.character()", "format()" etc...but in all cases i get the output of the dataframe itself en not just the content of the typen vector.

For example, say have I have 2 vectors...test_a and test_b

test_a <- read.csv2("test.csv", sep = ";", dec = ",")
test_b <- read_excel("test.xlsx")

x <- test_a ##(or test_b)
y <- as.character(x) ##this doesn't work :(


fig <- ggplot(x, aes(x = OUTCOME)) 
fig + geom_histogram(aes(color = SEX), 
                        breaks=seq(0, 1500, by = 1),
                        alpha = 1) +
        ggtitle(as.character(y))

As title of the graph I expect to get "test_a" or "test_b" as in "y" and not the numbers in test_a or test_b...Your help is appreciated a lot..

What you're doing is assigning test_a to a new object x. This doesnot bring the name to ggtitle but brings some values from test_a. — NelsonGon, Jan 27 '19 at 15:46
@NelsonGon: thnx for the typo comment :p....The reason I assign test_a to x is that i have test_a to test_m...and after that there is a large chunck of code where x is returning. — Andrei, Jan 27 '19 at 15:50
@markus i just want to use the text "test_a" and not the values from test_a... — Andrei, Jan 27 '19 at 15:53
@NelsonGon: output of str(x) Classes ‘tbl_df’, ‘tbl’ and 'data.frame': 27916 obs. of 44 variables; str(test_a) is the Same ;) — Andrei, Jan 27 '19 at 15:55
From your comment above I thought test_a was a data.frame of data.frames. — NelsonGon, Jan 27 '19 at 15:59
I think you can use `lapply` with a function that plots all the plots. Otherwise do it manually for each plot. — NelsonGon, Jan 27 '19 at 16:05
@NelsonGon true...I guess the simple question is: How could I convert all text after " — Andrei, Jan 27 '19 at 16:06
No need to save it as a variable. Just write it in `ggtitle("test_a")`. Otherwise x now takes on all data in test_a. — NelsonGon, Jan 27 '19 at 16:07

markus · Accepted Answer · 2019-01-27T16:06:32.147

2

We can use substitute and eval here

x <- substitute(iris)

ggplot(eval(x), aes(Sepal.Width, Sepal.Length)) +
  geom_point() +
  labs(title = x)

edited Jan 27 '19 at 16:06

answered Jan 27 '19 at 15:59

markus

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I think this is the same as just saying `title="iris"`. OP seems to want to "automate" it. – NelsonGon Jan 27 '19 at 16:00
1

@NelsonGon Thanks for your comment. Updated the answer. – markus Jan 27 '19 at 16:05
In this example, you still have to type "iris" everywhere. I acctually want this: x – Andrei Jan 27 '19 at 16:09
@Andrei Updated the answer, now it should give you what you are looking for. – markus Jan 27 '19 at 16:10
@markus...you rock!! this works – Andrei Jan 27 '19 at 16:22

How can I use the content of a vector as title in ggplot?

1 Answers1