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I have a csv file "fruit.csv" looking like that:

"Date","Fruit","Count"
2019-01-01,Apple,3
2019-01-01,Pear,5
2019-01-01,Banana,4
2019-02-01,Apple,4
2019-02-01,Pear,4
2019-02-01,Banana,6
...

I want to plot the data having the date in the x-axis and the number in the y-axis. Especially, i want the graph to only show the data of a certain fruit, e.g. only apples. This is what I have until now, plotting all fruits at once:

data <- read.csv("Path/to/fruit.csv")

data$Date <- as.Date(data$Date)

time_series <- xts(data$Count, order.by = data$Date)
dygraph(time_series)

What do I need to add, to specify the fruit I want to plot?

1 Answers1

1

Here are some approaches:

First, use dplyr to filter() the data ahead of time:

library(dplyr)
apples <- data %>%
  filter(Fruit == "Apple")
apples_ts <- xts(apples$Count, order.by = apples$Date)
dygraph(apples_ts)

Second, subset the data in a more traditional way ahead of time.

apples <- data[which(data$Fruit == "Apples"),]
apples_ts <- xts(apples$Count, order.by = apples$Date)
dygraph(apples_ts)

Third, subset the data in the call to xts:

apples_ts <- xts(data[data$Fruit == "Apple",]$Count, 
                 order.by = data[data$Fruit == "Apple",]$Date)
dygraph(apples_ts)

Fourth, write a custom function so you don't need to repeat this code for each fruit:

fruit_dygraph <- function(data, fruit) {
  fruit_ts <- xts(data[data$Fruit == fruit,]$Count, 
                 order.by = data[data$Fruit == fruit,]$Date)
  dygraph(fruit_ts)
  }
fruit_dygraph(data, fruit = "Apple")
Ben Norris
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  • Thanks a lot! Providing plenty approaches really helps me as a beginner to understand whats happening. –  Aug 10 '20 at 12:26
  • However, option #3 will give me an error: `undefined columns selected`. Is something missing there? –  Aug 10 '20 at 12:30
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    Option #3 was missing a critical comma in the second subset. #3 should work now. – Ben Norris Aug 10 '20 at 12:39
  • Almost there, I just found out, you still have to add `order.by = as.Date(data[...])` –  Aug 10 '20 at 12:40