plot3.R

# Reading data

setwd("I:/OneDrive/03_Data/01_Courses/Data Science Specialization/Exploratory data analysis/Project 1")
df <- read.csv("household_power_consumption.txt", sep = ";", na.strings = "?")

library(lubridate)

df$Date <- as.Date(df$Date, format = "%d/%m/%Y" )
df_sub <- subset(df, Date == ymd(070201) | Date == ymd(070202))
df_sub$Time <- strptime(df_sub$Time, format = "%H:%M:%S")
date(df_sub$Time) <- df_sub$Date
rm("df")

# Plot 3 function
plot3 <- function(df_sub){
  library(tidyr)
  library(dplyr)
  df_sub$Time <- as.POSIXct(df_sub$Time)
  df_metering <- tbl_df(df_sub) %>% gather(metering, m_value, 7:9)
  
  
  plot(df_metering$Time, df_metering$m_value, type = "n", xlab = "", ylab = "Energy sub metering")
  lines(df_sub$Time, df_sub$Sub_metering_1, col = "black")
  lines(df_sub$Time, df_sub$Sub_metering_2, col = "red")
  lines(df_sub$Time, df_sub$Sub_metering_3, col = "blue")
  
  legend("topright", lty = c(1, 1, 1), col = c("black", "red", "blue"), legend = c("Sub metering 1", "Sub metering 2", "Sub metering 3"))
  
}
  
# Plotting

png("plot3.png", width = 480, height = 480)
plot3(df_sub)
dev.off()