From 5eb407cca6cc5ed7b3734a7ba70716866ef7e7ba Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" Here we are creating a new object from an existing one: Using just this will only print the result and not actually change
If we want to modify If we forget to reassign this can cause subsequent steps to not work
as expected because we will not be working with the data that has been
modified.Why are my changes not taking effect? It’s making my results
-new_rivers <- sample(rivers, 5)
new_rivers
+## [1] 900 890 780 430 250
## [1] 350 2533 246 270 360
new_rivers
:
-new_rivers + 1
+## [1] 901 891 781 431 251
## [1] 351 2534 247 271 361
new_rivers
and save that modified
version, then we need to reassign new_rivers
like so:
-new_rivers <- new_rivers + 1
new_rivers
+## [1] 901 891 781 431 251
## [1] 351 2534 247 271 361
Error: object ‘X’ not found
operator:
rivers2 <- new_rivers + 1
rivers2
-## [1] 902 892 782 432 252
+## [1] 352 2535 248 272 362
library(readr)
library(tidyverse)
## ── Attaching core tidyverse packages ──────────────────────── tidyverse 2.0.0 ──
-## ✔ dplyr 1.1.2 ✔ purrr 1.0.1
-## ✔ forcats 1.0.0 ✔ stringr 1.5.0
-## ✔ ggplot2 3.4.2 ✔ tibble 3.2.1
-## ✔ lubridate 1.9.2 ✔ tidyr 1.3.0
+## ✔ dplyr 1.1.4 ✔ purrr 1.0.2
+## ✔ forcats 1.0.0 ✔ stringr 1.5.1
+## ✔ ggplot2 3.5.0 ✔ tibble 3.2.1
+## ✔ lubridate 1.9.3 ✔ tidyr 1.3.1
## ── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
## ✖ dplyr::filter() masks stats::filter()
## ✖ dplyr::lag() masks stats::lag()
@@ -391,10 +391,6 @@ Part 1
6. Read in the Charm City Circulator data using
read_circulator()
function from jhur
package
using the code supplied in the chunk.
-
-- Use the
str()
function to take a look at the data and
-learn about the column types.
-
circ <- read_circulator()
## Rows: 1146 Columns: 15
## ── Column specification ────────────────────────────────────────────────────────
@@ -404,6 +400,10 @@ Part 1
##
## ℹ Use `spec()` to retrieve the full column specification for this data.
## ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.
+
+- Use the
str()
function to take a look at the data and
+learn about the column types.
+
7. Use the mutate()
function to create a new column
named date_formatted
that is of Date
class.
The new variable is created from date
column. Hint: use
diff --git a/modules/Data_Cleaning/lab/Data_Cleaning_Lab.html b/modules/Data_Cleaning/lab/Data_Cleaning_Lab.html
index 3a81dfb4e..0912bc359 100644
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+++ b/modules/Data_Cleaning/lab/Data_Cleaning_Lab.html
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-
Data Cleaning Lab Key
+Data Cleaning Lab
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+h1.title {font-size: 38px;}
+h2 {font-size: 30px;}
+h3 {font-size: 24px;}
+h4 {font-size: 18px;}
+h5 {font-size: 16px;}
+h6 {font-size: 12px;}
+code {color: inherit; background-color: rgba(0, 0, 0, 0.04);}
+pre:not([class]) { background-color: white }
+
+
+code{white-space: pre-wrap;}
+span.smallcaps{font-variant: small-caps;}
+span.underline{text-decoration: underline;}
+div.column{display: inline-block; vertical-align: top; width: 50%;}
+div.hanging-indent{margin-left: 1.5em; text-indent: -1.5em;}
+ul.task-list{list-style: none;}
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+h1.title {font-size: 38px;}
+h2 {font-size: 30px;}
+h3 {font-size: 24px;}
+h4 {font-size: 18px;}
+h5 {font-size: 16px;}
+h6 {font-size: 12px;}
+code {color: inherit; background-color: rgba(0, 0, 0, 0.04);}
+pre:not([class]) { background-color: white }
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+code{white-space: pre-wrap;}
+span.smallcaps{font-variant: small-caps;}
+span.underline{text-decoration: underline;}
+div.column{display: inline-block; vertical-align: top; width: 50%;}
+div.hanging-indent{margin-left: 1.5em; text-indent: -1.5em;}
+ul.task-list{list-style: none;}
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+h1.title {font-size: 38px;}
+h2 {font-size: 30px;}
+h3 {font-size: 24px;}
+h4 {font-size: 18px;}
+h5 {font-size: 16px;}
+h6 {font-size: 12px;}
+code {color: inherit; background-color: rgba(0, 0, 0, 0.04);}
+pre:not([class]) { background-color: white }
+
+
+code{white-space: pre-wrap;}
+span.smallcaps{font-variant: small-caps;}
+span.underline{text-decoration: underline;}
+div.column{display: inline-block; vertical-align: top; width: 50%;}
+div.hanging-indent{margin-left: 1.5em; text-indent: -1.5em;}
+ul.task-list{list-style: none;}
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+Introduction to R: Homework 2
+
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+
+
+Instructions
+Completed homework should be submitted on CoursePlus as an
+Rmd file. Please see the course website for more
+information about submitting assignments: https://jhudatascience.org/intro_to_r/syllabus.html#submitting-assignments.
+Homework will be graded for correct output, not code style. All
+assignments are due at the end of the course. Please see the course
+website for more information about grading: https://jhudatascience.org/intro_to_r/syllabus.html#grading.
+## you can add more, or change...these are suggestions
+library(tidyverse)
+library(readr)
+library(dplyr)
+library(ggplot2)
+library(tidyr)
+
+
+Problem Set
+1. Create the following two objects.
+
+- Make an object “bday”. Assign it your birthday in day-month format
+(1-Jan).
+- Make another object “name”. Assign it your name. Make sure to use
+quotation marks for anything with text!
+
+2. Make an object “me” that is “bday” and “name” combined.
+3. Determine the data class for “me”.
+4. If I want to do me / 2
I get the following error:
+Error in me/2 : non-numeric argument to binary operator
.
+Why? Write your answer as a comment inside the R chunk below.
+The following questions involve an outside
+dataset.
+We will be working with a dataset from the “Kaggle” website, which
+hosts competitions for prediction and machine learning. More details on
+this dataset are here: https://www.kaggle.com/c/DontGetKicked/overview/background.
+5. Bring the dataset into R. The dataset is located at: https://jhudatascience.org/intro_to_r/data/kaggleCarAuction.csv.
+You can use the link, download it, or use whatever method you like for
+getting the file. Once you get the file, read the dataset in using
+read_csv()
and assign it the name cars
.
+6. Import the data “dictionary” from https://jhudatascience.org/intro_to_r/data/Carvana_Data_Dictionary_formatted.txt.
+Use the read_tsv()
function and assign it the name
+“key”.
+7. You should now be ready to work with the “cars” dataset.
+
+- Preview the data so that you can see the names of the columns. There
+are several possible functions to do this.
+- Determine the class of the first three columns using
+
str()
. Write your answer as a comment inside the R chunk
+below.
+
+8. How many cars (rows) are in the dataset? How many variables
+(columns) are recorded for each car?
+9. Filter out (i.e., remove) any vehicles that cost less than or
+equal to $5000 (“VehBCost”) or that have missing values. Replace the
+original “cars” object by reassigning the new filtered dataset to
+“cars”. How many vehicles are left after filtering?
+Hint: The filter()
function also
+removes missing values.
+10. From this point on, work with the filtered “cars” dataset from
+the above question. Given the average car loan today is 70 months,
+create a new variable (column) called “MonthlyPrice” that shows the
+monthly cost for each car (Divide “VehBCost” by 70). Check to make sure
+the new column is there.
+Hint: use the mutate()
function.
+11. What is the range of the manufacture year (“VehYear”) of the
+vehicles?
+12. Create a random sample with of mileage (odometer reading) from
+cars
. To determine the column that corresponds to mileage
+(The vehicle’s odometer reading), check the “key” corresponding to the
+data dictionary that you imported above in question 6. Use
+sample()
and pull()
. Remember that by default
+random samples differ each time you run the code.
+13. How many cars were from before 2004? What percent/proportion do
+these represent? Use:
+
+filter()
and nrow()
+group_by()
and summarize()
or
+sum()
+
+14. How many different vehicle manufacturers/makes (“Make”) are
+there?
+Hint: use length()
with
+unique()
or table()
. Remember to
+pull()
the right column.
+15. How many different vehicle models (“Model”) are there?
+16. Which vehicle color group had the highest mean acquisition cost
+paid for the vehicle at time of purchase, and what was this cost?
+Hint: Use group_by()
with
+summarize()
. To determine the column that corresponds to
+“acquisition cost paid for the vehicle at time of purchase”, check the
+“key” corresponding to the data dictionary that you imported above in
+question 6.
+17. Extend on the code you wrote for question 16. Use the
+arrange()
function to sort the output by mean acquisition
+cost.
+18. How many vehicles were red and have fewer than 30,000 miles? To
+determine the column that corresponds to mileage (The vehicle’s odometer
+reading), check the “key” corresponding to the data dictionary that you
+imported above in question 6. use:
+
+filter()
and count()
+filter()
and tally()
or
+sum()
+
+19. How many vehicles are blue or red? use:
+
+filter()
and count()
+filter()
and tally()
or
+sum()
+
+20. Select all columns in “cars” where the column names starts with
+“Veh” (using select()
and starts_with()
. Then,
+use colMeans()
to summarize across these columns.
+
+The following questions are not required for full credit, but can
+make up for any points lost on other questions.
+
+
+
+Bonus Practice
+A. Using “cars”, create a new binary (TRUEs and FALSEs) column to
+indicate if the car has an automatic transmission. Call the new column
+“is_automatic”.
+B. What is the average vehicle odometer reading for cars that are
+both RED and NISSANs? How does this compare with vehicles that do NOT
+fit this criteria?
+C. Among red Nissans, what is the distribution of vehicle ages?
+D. How many vehicles (using filter()
or
+sum()
) are made by Chrysler or Nissan and are white or
+silver?
+E. Make a boxplot (boxplot()
) that looks at vehicle age
+(“VehicleAge”) on the x-axis and odometer reading (“VehOdo”) on the
+y-axis.
+F. Knit your document into a report.
+You use the knit button to do this. Make sure all your code is
+working first!
+
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