I am writing my first R function.
IMDBmovierating <- function(movie){
link <- paste("http://www.omdbapi.com/?t=", movie, "&y=&plot=short&r=json", `sep = "")`
jsonData <- fromJSON(link)
df <- data.frame(jsonData)
}
And then nothing happens. Suspect it has something to do with return being needed. Not sure how I would write this.
To return df, simply write return(df):
IMDBmovierating <- function(movie){
link <- paste("http://www.omdbapi.com/?t=", movie, "&y=&plot=short&r=json", sep = "")
jsonData <- fromJSON(link)
df <- data.frame(jsonData)
return(df)
}
or, even simpler in this case, omit the last assignment:
IMDBmovierating <- function(movie){
link <- paste("http://www.omdbapi.com/?t=", movie, "&y=&plot=short&r=json", sep = "")
jsonData <- fromJSON(link)
data.frame(jsonData)
}
If the last expression evaluates to a result object, as data.frame(..) does, then this gets the return object of the enclosing expression and the explicit return statement may be omitted.
edit: and remove the back-ticks before sep and after you closing parenthesis
edit2: Of course MrFlick's comment is correct: the only thing really wrong with your code are the back-ticks that probably are simply a typo here on the site. Even the assignment produces the assigned value as a result object, but it is invisible. Hence, you can assign it, but it is not automatically printed on the console.
You simply need to evaluate the object at the end of your function so it will return a value. See the simple example below:
funA <- function(x) {
a <- x
}
funB <- function(x) {
b <- x
b
}
funA(1) # prints nothing
funB(1) # prints 'b'
[1] 1
EDIT:
As @MrFlick points out, both funA and funB return the evaluation of the last expression, but funA will not print anything. However, if you assign the output of funA(1) an object, that object will produce the value 1:
z <- funA(1)
z
[1] 1
z == funB(1)
[1] TRUE
The moral of the story is that you either need to assign the output of IMDBmovierating to an object, or explicitly evaluate df at the end of the function.
Looks like you just had a few typos.
Try this and dont forget to include your library to help people out when answering you. :)
library(RJSONIO)
IMDBmovierating <- function(movie){
link <- paste("http://www.omdbapi.com/?t=", movie,"&y=&plot=short&r=json", sep = "")
jsonData <- fromJSON(link)
df <- data.frame(jsonData)
}
test <- IMDBmovierating(1984)
test
return(df) line at the end, this function wouldn't work as expected. Seems my assumption was wrong.
data.frame(jsonData)instead ofdf <-data.frame(jsonData)print()that variable, you should be able to see the result. eg:f<-function(a) {b<-a+1}; x<-f(4); print(x)x <- 1; x,x <- 1or(x <- 1). And what about=operator.<-and=will behave identically, they both perform assignment. Whey you run an assignment expression, it will return invisibly. But when you runxor use()both of those are separate expressions so the invisible part will not apply and you'll see the value. If you need more details, it would probably be best to open your own new question.