Home > Articles

  • Print
  • + Share This
This chapter is from the book

14.3 reshape2

The next most common munging need is either melting data (going from column orientation to row orientation) or casting data (going from row orientation to column orientation). As with most other procedures in R, there are multiple functions available to accomplish these tasks, but we will focus on Hadley Wickham’s reshape2 package. We talk about Wickham a lot, but that is because his products have become so fundamental to the R developer’s toolbox.

14.3.1 melt

Looking at the Aid_00s data.frame, we see that each year is stored in its own column. That is, the dollar amount for a given country and program is found in a different column for each year. This is called a cross table, which while nice for human consumption, is not ideal for graphing with ggplot2 or for some analysis algorithms.

> head(Aid_00s)

  Country.Name                                      Program.Name
1  Afghanistan                         Child Survival and Health
2  Afghanistan         Department of Defense Security Assistance
3  Afghanistan                            Development Assistance
4  Afghanistan Economic Support Fund/Security Support Assistance
5  Afghanistan                                Food For Education
6  Afghanistan                  Global Health and Child Survival
  FY2000  FY2001   FY2002    FY2003     FY2004     FY2005     FY2006
1     NA      NA  2586555  56501189   40215304   39817970   40856382
2     NA      NA  2964313        NA   45635526  151334908  230501318
3     NA 4110478  8762080  54538965  180539337  193598227  212648440
4     NA   61144 31827014 341306822 1025522037 1157530168 1357750249
5     NA      NA       NA   3957312    2610006    3254408     386891
6     NA      NA       NA        NA         NA         NA         NA
      FY2007     FY2008     FY2009
1   72527069   28397435         NA
2  214505892  495539084  552524990
3  173134034  150529862    3675202
4 1266653993 1400237791 1418688520
5         NA         NA         NA
6         NA   63064912    1764252

We want it set up so that each row represents a single country-program-year entry with the dollar amount stored in one column. To achieve this we melt the data using melt from reshape2.

> library(reshape2)
> melt00 <- melt(Aid_00s, id.vars=c("Country.Name", "Program.Name"),
+                variable.name="Year", value.name="Dollars")
> tail(melt00, 10)

      Country.Name
24521     Zimbabwe
24522     Zimbabwe
24523     Zimbabwe
24524     Zimbabwe
24525     Zimbabwe
24526     Zimbabwe
24527     Zimbabwe
24528     Zimbabwe
24529     Zimbabwe
24530     Zimbabwe
                                                Program.Name   Year
24521                       Migration and Refugee Assistance FY2009
24522                                      Narcotics Control FY2009
24523 Nonproliferation, Anti-Terrorism, Demining and Related FY2009
24524                            Other Active Grant Programs FY2009
24525                                Other Food Aid Programs FY2009
24526                                 Other State Assistance FY2009
24527                                 Other USAID Assistance FY2009
24528                                            Peace Corps FY2009
24529                                                Title I FY2009
24530                                               Title II FY2009
        Dollars
24521   3627384
24522        NA
24523        NA
24524   7951032
24525        NA
24526   2193057
24527  41940500
24528        NA
24529        NA
24530 174572685

The id.vars argument specifies which columns uniquely identify a row.

After some manipulation of the Year column and aggregating, this is now prime for plotting, as shown in Figure 14.1. The plot uses faceting, enabling us to quickly see and understand the funding for each program over time.

> library(scales)
> # strip the "FY" out of the year column and convert it to numeric
> melt00$Year <- as.numeric(str_sub(melt00$Year, start=3, 6))
> # aggregate the data so we have yearly numbers by program
> meltAgg <- aggregate(Dollars ~ Program.Name + Year, data=melt00,
+                      sum, na.rm=TRUE)
> # just keep the first 10 characters of program name
> # then it will fit in the plot
> meltAgg$Program.Name <- str_sub(meltAgg$Program.Name, start=1,
+                                 end=10)
>
> ggplot(meltAgg, aes(x=Year, y=Dollars)) +
+     geom_line(aes(group=Program.Name)) +
+     facet_wrap(~ Program.Name) +
+     scale_x_continuous(breaks=seq(from=2000, to=2009, by=2)) +
+     theme(axis.text.x=element_text(angle=90, vjust=1, hjust=0)) +
+     scale_y_continuous(labels=multiple_format(extra=dollar,
+                                               multiple="B"))
Figure 14.1

Figure 14.1 Plot of foreign assistance by year for each of the programs.

14.3.2 dcast

Now that we have the foreign aid data melted, we cast it back into the wide format for illustration purposes. The function for this is dcast, and it has trickier arguments than melt. The first is the data to be used, in our case melt00. The second argument is a formula where the left side specifies the columns that should remain columns and the right side specifies the columns that should become column names. The third argument is the column (as a character) that holds the values to be populated into the new columns, representing the unique values of the right side of the formula argument.

> cast00 <- dcast(melt00, Country.Name + Program.Name ~ Year,
+                 value.var="Dollars")
> head(cast00)

  Country.Name                                      Program.Name 2000
1  Afghanistan                         Child Survival and Health   NA
2  Afghanistan         Department of Defense Security Assistance   NA
3  Afghanistan                            Development Assistance   NA
4  Afghanistan Economic Support Fund/Security Support Assistance   NA
5  Afghanistan                                Food For Education   NA
6  Afghanistan                  Global Health and Child Survival   NA
     2001     2002      2003       2004       2005       2006
1      NA  2586555  56501189   40215304   39817970   40856382
2      NA  2964313        NA   45635526  151334908  230501318
3 4110478  8762080  54538965  180539337  193598227  212648440
4   61144 31827014 341306822 1025522037 1157530168 1357750249
5      NA       NA   3957312    2610006    3254408     386891
6      NA       NA        NA         NA         NA         NA
        2007       2008       2009
1   72527069   28397435         NA
2  214505892  495539084  552524990
3  173134034  150529862    3675202
4 1266653993 1400237791 1418688520
5         NA         NA         NA
6         NA   63064912    1764252
  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020