Global Active Power Time Series - Exploratory Data Analysis - Coursera

Exploratory Graphing - Global Active Power

Download and Pre-process the Data

download <- download.file("https://d396qusza40orc.cloudfront.net/exdata%2Fdata%2Fhousehold_power_consumption.zip",destfile = "temp")
unzip("temp")
unlink("temp")

hpc <- read.table("household_power_consumption.txt", 
                  sep = ";", header = TRUE, na.strings = "?")

hpc$dt <- strptime(paste(hpc$Date, hpc$Time), "%d/%m/%Y %H:%M:%S")
hpc$Date <- as.Date(hpc$Date, "%d/%m/%Y")

hpc_sub <- hpc %>% filter(Date >= as.Date("2007-02-01")) %>%
  filter( Date <= as.Date("2007-02-02"))

Plot 1

hist(hpc_sub$Global_active_power, col = "red", 
     xlab = "Global Active Power (kilowatts)", 
     ylab = "Frequency", main = "Global Active Power", 
     breaks = 13, ylim = c(0,1200), xlim = c(0, 6))

Plot 2

plot(hpc_sub$dt, hpc_sub$Global_active_power, 
     type = "l", xlab = "", 
     ylab = "Global Active Power (kilowatts)")

Plot 3

plot(hpc_sub$dt, hpc_sub$Sub_metering_1, 
     type = "l", xlab = "", 
     ylab = "Energy sub metering")
points(hpc_sub$dt, hpc_sub$Sub_metering_2, type = "l", col = "red")
points(hpc_sub$dt, hpc_sub$Sub_metering_3, type = "l", col = "blue")

legend("topright", lty = 1, col = c("black", "red", "blue"), 
       legend = c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"))

Plot 4

par(mfrow=c(2,2))
par(mar=c(4,4,4,4))

plot(hpc_sub$dt, hpc_sub$Global_active_power, 
     type = "l", xlab = "", ylab = "Global Active Power (kilowatts)")
plot(hpc_sub$dt, hpc_sub$Voltage, type = "l", xlab = "datetime", ylab = "Voltage")
plot(hpc_sub$dt, hpc_sub$Sub_metering_1, 
     type = "l", xlab = "", ylab = "Energy sub metering")

points(hpc_sub$dt, hpc_sub$Sub_metering_2, type = "l", col = "red")
points(hpc_sub$dt, hpc_sub$Sub_metering_3, type = "l", col = "blue")

legend("topright", lty = 1, col = c("black", "red", "blue"), 
       legend = c("Sub_metering_1", "Sub_metering_2", "Sub_metering_3"), 
       bty = "n", cex = 0.8)
plot(hpc_sub$dt, hpc_sub$Global_reactive_power, 
     type = "l", xlab = "datetime", ylab = "Global_reactive_power")

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