# Tell R we are using the ggplot2 plotting library.  This is the equivalent of an import statement in Python.
library(ggplot2)

# Read the file into a dataframe
guns <- read.csv("nics-firearm-background-checks.csv")

# There are a lot of columns in the dataframe, so we will only keep the first 8 columns,
# to make it easier to see what is happening in the dataframe.
guns <- guns[,1:8]

# Tell R that the month column contains dates, so that it can interpret them that way.
# Unfortunately, the built-in data converter in R needs the day of the month, which our data doesn't have. 
# So we will add -01 to all the dates, so that the date is the 1st of each month.
guns$month <- paste(guns$month,"-01",sep="")
# Convert the month column into R dates
guns$month <- as.Date(guns$month)

# ggplot works by adding together the components that make up the plot:
# set up the plot using the guns dataframe, with x being the month column data and y being the handgun column data
ggplot(guns,aes(x = month, y = handgun)) + 
  # add ploints to the plot that are red  (if you don't put a color, the default is black)
 geom_point(color = "red") +
  # add a title to the plot
 ggtitle("# of handgun background checks")

# The previous plot plotted all numbers for all states for all dates, so it was hard to understand what was happening.
# Let's just look at New York.
# Make a new dataframe with only the New York data.
guns_NY <- subset(guns,subset = state == "New York")

# Make the same plot as above, but using only the New York state data.
ggplot(guns_NY,aes(x = month, y = handgun)) + geom_point(color = "red") +
  ggtitle("# of handgun background checks")

# This is the same as the previous plot, but uses a line instead of points to show the data.
ggplot(guns_NY,aes(x = month, y = handgun)) + geom_line(color = "red") +
  ggtitle("# of handgun background checks")

# We will make a dataframe with only the data from 5 states.
guns_5states <- subset(guns,subset = state == "New York" | state == "California" | state == "North Carolina" | state == "Alaska" | state == "Louisiana")

# This is the same as the previous plot, but uses the 5 states dataframe instead of the one with only New York.
# Also, we add the option color = factor(state) to tell R that all rows with the same state should have the same color.
ggplot(guns_5states,aes(x = month, y = handgun,color = factor(state))) + 
  geom_line() +
  ggtitle("# of handgun background checks")

# This is the same as the previous plot, but we plot the long_gun column instead of the handgun column.
ggplot(guns_5states,aes(x = month, y = long_gun,color = factor(state))) + 
  geom_line() +
  ggtitle("# of handgun background checks")