exercise

exercise-1/exercise.R

@@ -12,12 +12,13 @@ vehicle <- add_rownames(mtcars, var='car')
 # Function to debug:
 # Given a number of forward gears and a number of cylinders, what is the 
 # Name of the car with the best mpg?
-BestGearsCyl <- functon(gears, cylinders) {
-  ret <- vehicles %>%  
+BestGearsCyl <- function(gears, cylinders) {
+  ret <- vehicle %>%  
         filter(gear == gears, cyl == cylinders) %>% 
-        filter(mgp = max(mpg)) %>% 
+        filter(mpg == max(mpg)) %>% 
         select(car)
+  return(ret)
 }
 
 # Get the best mpg car for 6 cylinder cars with 4 gears
-answer <- BestGearsCyl(6, 4)
+answer <- BestGearsCyl(cylinders=6, gears=4)

exercise-2/exercise.R

@@ -8,11 +8,23 @@ setwd('~/Documents/info-201/m10-apis/exercise-2/')
 
 
 # Write a function that allows you to specify an artist, and returns the top 10 tracks of that artist
+GetArtist <- function(artist) {
+  base <- 'https://api.spotify.com/v1/'
+  search <- paste("search?", "q=", artist, sep = "")
+  type <- '&type=artist'
+  query.url <- paste0(base, search, type)
+  data <- fromJSON(query.url)
+  artist.id <- data$artists$items$id[1]
+  album.query <- paste0(base, 'artists/', artist.id, '/top-tracks?country=US')
+  top.tracks <- fromJSON(album.query)
+  return(top.tracks)
+}
 
+#result <- GetArtist("adele")
 
 
 # What are the top 10 tracks by Nelly?
-
+result <- GetArtist('Nelly')
 
 
 

exercise-3/exercise.R

@@ -1,15 +1,16 @@
 ### Exercise 3 ###
 library(jsonlite)
 library(dplyr)
+load("nelly_tracks.Rdata")
 # Use the `load` function to load in the nelly_tracks file.  That should make the data.frame
 # `top_nelly` available to you
 
 
 # Use the `flatten` function to flatten the data.frame -- note what differs!
-
+flatten(top.nelly)
 
 # Use your `dplyr` functions to get the number of the songs that appear on each albumt
-
+number.songs <- filter(flatten(top.nelly), album.album_type == 'album') %>% select(track_number)
 
 
 # Bonus: perform both of the steps above in one line (one statement)

exercise-4/exercise.r

@@ -1,43 +1,48 @@
 # Install and load the jsonlite package
-
+library(jsonlite)
+library(dplyr)
 # Make a variable base.url that has the same base url from the omdb documentation.
 # (Hint: visit https://www.omdbapi.com/ to find the base url)
-
+base.url <- "http://www.omdbapi.com/?"
 # Make a variable called movie that has the names of your favorite movie
-
+movie <- "Interstellar"
 # Make a variable called move.no.spaces that holds movie where all the spaces
 # are replaced with the '+' character
-
+move.no.spaces <- gsub(" ", "+", movie)
 # Make a variable called "parameters" that holds a string with the parameters
 # to pass to the API. View the OMDb documentation to see which parameters
 # are available. Remember to separate parameters with the '&' character.
-
+parameters <- paste0("t=", move.no.spaces, "&r=json")
 # Make a variable called request that is a string of a request URL made up of the base URL
 # and the parameters string
-
+request <- paste0(base.url, parameters)
 # Use fromJSON to retrieve JSON data from the omdb api using your request URL.
 # Store the result in a variable called movie.data
-
+movie.data <- fromJSON(request)
 # Make movie_data into a data frame using as.data.frame
-
+movie.data <- as.data.frame(movie.data) %>% flatten()
 # Write a function called Director that accepts a data frame of movie info and returns
 # A vector of strings that states a movie and the director of said movie.
-
+Director <- function(movie.info) {
+  director <- movie.info$Director
+  name <- movie.info$Title
+  return(paste(name, "is directed by", director))
+}
 # Call Director with your favorite movie, and assign it to the variable movie.director
-
+movie.director <- Director(movie.data)
 # Bonus 
 
 # Knowing the director of on movie is okay, but it'd be great to know the directors of different
 # movies. 
 
 # Start by making a vecotr of movies and save it to the variable movie.list
-
+movie.list <- c("Interstallar", "Saw", "Kill Bill")
 # Remove spaces from each movie title
-
+movie.list <- gsub(" ", "+", movie.list)
 # Prepare this list to be passed in as parameters for the API
-
+parameter <- paste0("t=", movie.list, "&r=json")
 # Create API URL request and assign it to the variable api.request
-
+api.request <- fromJSON()
 # For every entry in the vector api.request, APPLY the function fromJSON to make a list of lists
 # one entry for each request and assign this to a variable called data. 
 # (Hint: ?lapply. It's similar a 'for' loop but better!)