Lesson 2 Complete

.gitignore

@@ -0,0 +1,4 @@
+.Rproj.user
+.Rhistory
+.RData
+.Ruserdata

lesson2/What_is_a_RMD_file.Rmd

@@ -1,9 +1,16 @@
-Title
+Speed and Stopping Distances of Cars
 ========================================================
 
 This is an R Markdown document or RMD. Markdown is a simple formatting syntax for authoring web pages (click the **Help** toolbar button for more details on using R Markdown).
 
+```{r}
+?cars
+str(cars)
+```
 
+```{r fig.width=7, fig.height=6}
+plot(cars)
+```
 
 
 

lesson2/demystifying.R

@@ -55,7 +55,7 @@ numbers
 udacious <- c("Chris Saden", "Lauren Castellano",
               "Sarah Spikes","Dean Eckles",
               "Andy Brown", "Moira Burke",
-              "Kunal Chawla", YOUR_NAME)
+              "Kunal Chawla", "Dustin Pianalto")
 
 # Notice how R updates 'udacious' in the workspace.
 # It should now say something like 'chr[1:8]'.

lesson2/demystifyingR2.Rmd

@@ -24,13 +24,14 @@ Subset the data so that you create a new data frame that contains
 cars that get 23 or more mpg (miles per gallon). Save it to a new data
 frame called efficient.
 ```{r}
-
+efficient <- mtcars[mtcars$mpg >= 23,]
+efficient
 ```
 
 3. How many cars get more than 23 mpg? Use one of the commands you
 learned in the demystifying.R to answer this question.
 ```{r}
-
+dim(efficient)
 ```
 
 4. We can also use logical operators to find out which car(s) get greater
@@ -66,13 +67,15 @@ Now you try some.
 6. Print the cars that have a 1/4 mile time (qsec) less than or equal to
 16.90 seconds to the console.
 ```{r}
-
+mtcars[mtcars$qsec <= 16.90,]
 ```
 
 7. Save the subset of cars that weigh under 2000 pounds (weight is measured in lb/1000)
 to a variable called lightCars. Print the numbers of cars and the subset to the console.
 ```{r}
-
+lightCars <- mtcars[mtcars$wt <= 2.0,]
+dim(lightCars)
+lightCars
 ```
 
 8. You can also create new variables in a data frame. Let's say you wanted
@@ -104,7 +107,7 @@ Open the table of values to see what values year takes on.
 
 Drop the year variable from the data set.
 ```{r}
-
+mtcars <- subset(mtcars, select = -year)
 ```
 
 
@@ -164,6 +167,10 @@ answer a question to continue on in Lesson 2.
 Which car(s) have an mpg (miles per gallon) greater than or equal to 30
 OR hp (horsepower) less than 60? Create an R chunk of code to answer the question.
 
+```{r}
+answer = mtcars[mtcars$mpg >= 30 | mtcars$hp < 60,]
+answer
+```
 
 
 Once you have the answer, go the [Udacity website](https://www.udacity.com/course/viewer#!/c-ud651/l-729069797/e-804129319/m-811719066) to continue with Lesson 2.

lesson2/lesson2.Rproj

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+Version: 1.0
+
+RestoreWorkspace: Default
+SaveWorkspace: Default
+AlwaysSaveHistory: Default
+
+EnableCodeIndexing: Yes
+UseSpacesForTab: Yes
+NumSpacesForTab: 2
+Encoding: UTF-8
+
+RnwWeave: Sweave
+LaTeX: pdfLaTeX

lesson2/reddit_graphs.R

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+reddit <- read.csv('reddit.csv')
+
+table(reddit$employment.status)
+summary(reddit)
+
+library(ggplot2)
+age.ordered <- ordered(reddit$age.range, levels = c('Under 18', '18-24', '25-34', '45-54', '55-64', '65 or Above', 'NA'))
+qplot(data = reddit, x = age.ordered)
+qplot(data=reddit, x=income.range)
+