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Don't look at me…I do what he does — just slower. #rstats avuncular • ?Resistance Fighter • Cook • Christian • [Master] Chef des Données de Sécurité @ @rapid7

If you do enough web scraping, you’ll eventually hit a wall that the trusty httr verbs (that sit beneath rvest) cannot really overcome: dynamically created content (via javascript) on a site. If the site was nice enough to use XHR requests to load the dynamic content, you can generally still stick with httr verbs — if you can figure out what those requests are — and code-up the right parameters (browser “Developer Tools” menus/views and my curlconverter package are super handy for this). Unfortunately, some sites require actual in-page rendering and that’s when scraping turns into a modest chore.

For dynamic sites, the RSelenium and/or seleniumPipes packages are super-handy tools to have in the toolbox. They interface with Selenium which is a feature-rich environment/ecosystem for automating browser tasks. You can programmatically click buttons, press keys, follow links and extract page content because you’re scripting actions in an actual browser or a browser-like tool such as phantomjs. Getting the server component of Selenium running was often a source of pain for R folks, but the new docker images make it much easier to get started. For truly gnarly scraping tasks, it should be your go-to solution.

However, sometimes all you need is the rendering part and for that, there’s a new light[er]weight alternative dubbed Splash. It’s written in python and uses QT webkit for rendering. To avoid deluging your system with all of the Splash dependencies you can use the docker images. In fact, I made it dead easy to do so. Read on!

Going for a dip

The intrepid Winston Chang at RStudio started a package to wrap Docker operations and I’ve recently joind in the fun to add some tweaks & enhancements to it that are necessary to get it on CRAN. Why point this out? Since you need to have Splash running to work with it in splashr I wanted to make it as easy as possible. So, if you install Docker and then devtools::install_github("wch/harbor") you can then devtools::install_github("hrbrmstr/splashr") to get Splash up and running with:

library(splashr)

install_splash()
splash_svr <- start_splash()

The install_splash() function will pull the correct image to your local system and you’ll need that splash_svr object later on to stop the container. Now, you can have Splash running on any host, but this post assumes you’re running it locally.

We can test to see if the server is active:

splash("localhost") %>% splash_active()
## Status of splash instance on [http://localhost:8050]: ok. Max RSS: 70443008

Now, we’re ready to scrape!

We’ll use this site — http://www.techstars.com/companies/ — mentioned over at DataCamp’s tutorial since it doesn’t use XHR but does require rendering and it doesn’t prohibit scraping in the Terms of Service (don’t violate Terms of Service, it is both unethical and could get you blocked, fined or worse).

Let’s scrape the “Summary by Class” table. Here’s an excerpt along with the Developer Tools view:

You’re saying “HEY. That has <table> in the HTML so why not just use rvest? Well, you can validate the lack of <table>s in the “view source” view of the page or with:

library(rvest)

pg <- read_html("http://www.techstars.com/companies/")
html_nodes(pg, "table")
## {xml_nodeset (0)}

Now, let’s do it with splashr:

splash("localhost") %>% 
  render_html("http://www.techstars.com/companies/", wait=5) -> pg
  
html_nodes(pg, "table")
## {xml_nodeset (89)}
##  [1] <table class="table75"><tbody>\n<tr>\n<th>Status</th>\n        <th>Number of Com ...
##  [2] <table class="table75"><tbody>\n<tr>\n<th colspan="2">Impact</th>\n      </tr>\n ...
##  [3] <table class="table75"><tbody>\n<tr>\n<th>Class</th>\n        <th>#Co's</th>\n   ...
##  [4] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Anywhere 2017 Q1</th>\ ...
##  [5] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Atlanta 2016 Summer</t ...
##  [6] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Austin 2013 Fall</th>\ ...
##  [7] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Austin 2014 Summer</th ...
##  [8] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Austin 2015 Spring</th ...
##  [9] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Austin 2016 Spring</th ...
## [10] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Barclays 2014</th>\n   ...
## [11] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Barclays 2015 Spring</ ...
## [12] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Barclays 2016 Winter</ ...
## [13] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Barclays Cape Town 201 ...
## [14] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Barclays NYC 2015 Summ ...
## [15] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Barclays NYC 2016 Summ ...
## [16] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Barclays Tel Aviv 2016 ...
## [17] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Berlin 2015 Summer</th ...
## [18] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Berlin 2016 Summer</th ...
## [19] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Boston 2009 Spring</th ...
## [20] <table><tbody>\n<tr>\n<th class="batch_class" colspan="4">Boston 2010 Spring</th ...
## ...##

We need to set the wait parameter (5 seconds was likely overkill) to give the javascript callbacks time to run. Now you can go crazy turning that into data.

Candid Camera

You can also take snapshots (pictures) of websites with splashr, like this (apologies if you start drooling on your keyboard):

splash("localhost") %>% 
  render_png("https://www.cervelo.com/en/triathlon/p-series/p5x")

The snapshot functions return magick objects, so you can do anything you’d like with them.

HARd Work

Since Splash is rendering the entire site (it’s a real browser), it knows all the information about the various components of a page and can return that in HAR format. You can retrieve this data and use John Harrison’s spiffy HARtools package to visualize and further analyze the data. For the sake of brevity, here’s just the main print() output from a site:

splash("localhost") %>% 
  render_har("https://www.r-bloggers.com/")

## --------HAR VERSION-------- 
## HAR specification version: 1.2 
## --------HAR CREATOR-------- 
## Created by: Splash 
## version: 2.3.1 
## --------HAR BROWSER-------- 
## Browser: QWebKit 
## version: 538.1 
## --------HAR PAGES-------- 
## Page id: 1 , Page title: R-bloggers | R news and tutorials contributed by (750) R bloggers 
## --------HAR ENTRIES-------- 
## Number of entries: 130 
## REQUESTS: 
## Page: 1 
## Number of entries: 130 
##   -  https://www.r-bloggers.com/ 
##   -  https://www.r-bloggers.com/wp-content/themes/magazine-basic-child/style.css 
##   -  https://www.r-bloggers.com/wp-content/plugins/mashsharer/assets/css/mashsb.min.cs... 
##   -  https://www.r-bloggers.com/wp-content/plugins/wp-to-twitter/css/twitter-feed.css?... 
##   -  https://www.r-bloggers.com/wp-content/plugins/jetpack/css/jetpack.css?ver=4.4.2 
##      ........ 
##   -  https://scontent.xx.fbcdn.net/v/t1.0-1/p50x50/10579991_10152371745729891_26331957... 
##   -  https://scontent.xx.fbcdn.net/v/t1.0-1/p50x50/14962601_10210947974726136_38966601... 
##   -  https://scontent.xx.fbcdn.net/v/t1.0-1/c0.8.50.50/p50x50/311082_286149511398044_4... 
##   -  https://scontent.xx.fbcdn.net/v/t1.0-1/p50x50/11046696_917285094960943_6143235831... 
##   -  https://static.xx.fbcdn.net/rsrc.php/v3/y2/r/0iTJ2XCgjBy.png

FIN

You can also do some basic scripting in Splash with lua and coding up an interface with that capability is on the TODO as is adding final tests and enabling tweaking the Docker configurations to support more fun things that Splash can do.

File an issue on github if you have feature requests or problems and feel free to jump on board with a PR if you’d like to help put the finishing touches on the package or add some features.

Don’t forget to stop_splash(splash_svr) when you’re finished scraping!

I made a promise to someone that my next blog would be about stringi vs stringr and I intend to keep said promise.

stringr and stringi do “string operations”: find, replace, match, extract, convert, transform, etc.

The stringr package is now part of the tidyverse and is 100% focused on string processing and is pretty much a wrapper package for stringi. The stringi package wraps chunks of the icu4c library but the stringi API frmaing was actually based on the patterns in the stringr package API. stringr did not wrap stringi at the time but does now and stringi strays a bit (on occasion) from string processing since the entire icu4c library is at it’s disposal. Confused? Good! There’s more!

The impetus for asking me to blog about this is that I’m known to say “just use stringi” in situations where someone has taken a stringr “shortcut”. Let me explain why.

Readers Digest

First, you need to read pages 4-5 of the stringi manual [PDF] and then the stringr vignette. I’m not duplicating the information on those pages. The TL;DR on them is:

  • that stringr makes some (valid) assumptions about defaults for the stringi calls it wraps
  • stringr is much easier to initially grok as it’s very focused and has far fewer functions
  • they both use ICU regular expressions
  • stringi includes more than string processing and has far more total functions:

As noted, stringr wraps stringi calls (for the most part) and some of the stringr functions reference more than one stringi function:

That’s my primary defense for “just use stringi” — stringr “just uses” it and you are forced to install stringi on every system stringr is on, so why introduce another dependency into your code?

All Wrapped Up

These are the stringr functions with a 1:~1 correspondence to stringi functions:

stri_c stri_conv stri_count stri_detect stri_dup stri_extract stri_extract_all stri_join stri_length stri_locate stri_locate_all stri_match stri_match_all stri_order stri_pad stri_replace stri_replace_all stri_replace_na stri_sort stri_split stri_split_fixed stri_sub stri_sub<- stri_subset stri_trim stri_wrap

I used 1:~1 since at the heart of the string processing capabilities of both packages lies the concept of granular control of matching behaviour. Specifically, there are four modes (so it’s really 1:4?):

  • fixed: Compare literal bytes in the string. This is very fast, but not usually what you want for non-ASCII character sets
  • coll: Compare strings respecting standard collation rules
  • regex: The default. Uses ICU regular expressions
  • boundary: Match boundaries between things

stringr has function modifiers around pattern to handle those whereas stringi requires explicit function calls. So, you’d do the following to replace a fixed char/byte sequence in each package:

  • stri_replace_all_fixed("Lorem i.sum dolor sit amet, conse.tetur adipisicing elit.", ".", "#")
  • str_replace_all("Lorem i.sum dolor sit amet, conse.tetur adipisicing elit.", fixed("."), "#")

In that case there’s not much in the way of keystroke savings, but the default mode of stringr is to use regex replacement and you do save both an i and _regex for that but add one more function call in-between you and your goal. When you work with multi-gigabyte character structures (as I do), those milliseconds often add up. If keystrokes > milliseconds in your workflow, you may want to stick with stringr.

Treasure Hunting in stringi

If you take some time to look at what’s in stringi you’ll find quite a bit (I excluded the fixed/coll/reged/boundary versions for brevity):

That’s an SVG, so zoom in as much as you need to to read it.

These are stringi gems:

  • stri_stats_general (stats abt a character vector)
  • stri_trans_totitle (For When You Want Title Case)
  • stri_flatten (paste0 but better defaults)
  • stri_rand_strings (random strings)
  • stri_rand_lipsum (random Lorem Ipsum lines!)
  • stri_count_words, stri_extract_all_words, stri_extract_first_words, stri_extract_last_words

Plus it has some helpful operators:

  • %s!=%, %s!==%, %s+%, %s<%, %s<=%, %s==%, %s===% %s>%, %s>=%, %stri!=%, %stri!==%, %stri+%, %stri<%, %stri<=%, %stri==%, %stri===%, %stri>%, %stri>=%

Of those, %s+% is ++handy for string concatenation.

Prior to readr, these were my go-to line/raw readers/writer: stri_read_raw, stri_read_lines, and stri_write_lines.

It also handles gnarly character encoding operations in a cross-platform, predictable manner.

FIN

To do a full comparison justice would have required writing a mini-book which is something I can’t spare cycles on, so my primary goals were to make sure folks knew stringr wrapped stringi and to show that stringi has much more to offer than you probably knew. If you start to get hooked on some of the more “fun” or utilitarian functions in stringi it’s probably worth switching to it. If string ops are ancillary operations to you and you normally work in regex-land, then you’re not missing out on anything and can save a few keystrokes here and there by using stringr.

Comments are extremely encouraged for this post as I’m curious if you know about stringi before and when/where/how you use it vs stringr (or, why you don’t).

I was enthused to see a mention of this on the GDELT blog since I’ve been working on an R package dubbed newsflash to work with the API that the form front-ends.

Given the current climate, I feel compelled to note that I’m neither a Clinton supporter/defender/advocate nor a ? supporter/defender/advocate) in any way, shape or form. I’m only using the example for replication and I’m very glad the article author stayed (pretty much) non-partisan apart from some color commentary about the predictability of network coverage of certain topics.

For now, the newsflash package is configured to grab raw count data, not the percent summaries since folks using R to grab this data probably want to do their own work with it. I used the following to try to replicate the author’s findings:

library(newsflash)
library(ggalt) # github version
library(hrbrmisc) # github only
library(tidyverse)
starts <- seq(as.Date("2015-01-01"), (as.Date("2017-01-26")-30), "30 days")
ends <- as.character(starts + 29)
ends[length(ends)] <- ""

pb <- progress_estimated(length(starts))
emails <- map2(starts, ends, function(x, y) {
  pb$tick()$print()
  query_tv("clinton", "email,emails,server", timespan="custom", start_date=x, end_date=y)
})

clinton_timeline <- map_df(emails, "timeline")

sum(clinton_timeline$value)
## [1] 34778

count(clinton_timeline, station, wt=value, sort=TRUE) %>%
  mutate(pct=n/sum(n), pct_lab=sprintf("%s (%s)", scales::comma(n), scales::percent(pct)),
         station=factor(station, levels=rev(station))) -> timeline_df

timeline_df

## # A tibble: 7 × 4
##             station     n         pct        pct_lab
##              <fctr> <int>       <dbl>          <chr>
## 1          FOX News 14807 0.425757663 14,807 (42.6%)
## 2      FOX Business  7607 0.218730232  7,607 (21.9%)
## 3               CNN  5434 0.156248203  5,434 (15.6%)
## 4             MSNBC  4413 0.126890563  4,413 (12.7%)
## 5 Aljazeera America  1234 0.035482201   1,234 (3.5%)
## 6         Bloomberg   980 0.028178734     980 (2.8%)
## 7              CNBC   303 0.008712404     303 (0.9%)

NOTE: I had to break up the queries since the bulk one across the two dates bump up against the API limits and may be providing helper functions for that before CRAN release.

While my package matches the total from the news article and sample query: 34,778 results my percentages are different since it’s the percentages across the raw counts for the included stations. “Percent of Sentences” (result “n” divided by the number of all sentences for each station in the time frame) — which the author used — seems to have some utility so I’ll probably add that as a query parameter or add a new function.

Tidy news text

The package also is designed to work with the tidytext package (it’s on CRAN) and provides a top_text() function which can return a tidytext-ready tibble or a plain character vector for use in other text processing packages. If you were curious as to whether this API has good data behind it, we can take a naive peek with the help of tidytext:

library(tidytext)

tops <- map_df(emails, top_text)
anti_join(tops, stop_words) %>% 
  filter(!(word %in% c("clinton", "hillary", "server", "emails", "mail", "email",
                       "mails", "secretary", "clinton's", "secretary"))) %>% 
  count(word, sort=TRUE) %>% 
  print(n=20)

## # A tibble: 26,861 × 2
##             word     n
##            <chr> <int>
## 1        private 12683
## 2     department  9262
## 3            fbi  7250
## 4       campaign  6790
## 5     classified  6337
## 6          trump  6228
## 7    information  6147
## 8  investigation  5111
## 9         people  5029
## 10          time  4739
## 11      personal  4514
## 12     president  4448
## 13        donald  4011
## 14    foundation  3972
## 15          news  3918
## 16     questions  3043
## 17           top  2862
## 18    government  2799
## 19          bill  2698
## 20      reporter  2684

I’d say the API is doing just fine.

Fin

The package also has some other bits from the API in it and if this has piqued your interest, please leave all package feature requests or problems as a github issue.

Many thanks to the Internet Archive / GDELT for making this API possible. Data like this would be amazing in any time, but is almost invaluable now.

I need to be up-front about something: I’m somewhat partially at fault for ? being elected. While I did not vote for him, I could not in any good conscience vote for his Democratic rival. I wrote in a ticket that had one Democrat and one Republican on it. The “who” doesn’t matter and my district in Maine went abundantly for ?’s opponent, so there was no real impact of my direct choice but I did actively point out the massive flaws in his opponent. Said flaws were many and I believe we’d be in a different bad place, but not equally as bad of a place now with her. But, that’s in the past and we’ve got a new reality to deal with, now.

This is a (hopefully) brief post about finding a way out of this mess we’re in. It’s far from comprehensive, but there’s honest-to-goodness evil afoot that needs to be met head on.

Brand Damage

You’ll note I’m not using either of their names. Branding is extremely important to both of them, but is the almost singular focus of ?. His name is his hotel brand, company brand and global identifier. Using it continues to add it to the history books and can only help inflate the power of that brand. First and foremost, do not use his name in public posts, articles, papers, etc. “POTUS”, “The President”, “The Commander in Chief”, “?” (chosen to match his skin/hair color, complexion and that comb-over tuft) are all sufficient references since there is date-context with virtually anything we post these days. Don’t help build up his brand. Don’t populate historical repositories with his name. Don’t give him what he wants most of all: attention.

Document and Defend with Data

Speaking of the historical record, we need to be blogging and publishing regularly the actual facts based on data. We also need to save data as there’s signs of a deliberate government purge going on. I’m not sure how successful said purge will be in the long run and I suspect that the long-term effects of data purging and corruption by this administration will have lasting unintended consequences.

Join/support @datarefuge to save data & preserve the historical record.

Install the Wayback Machine plugin and take the 2 seconds per site you visit to click it.

Create blog posts, tweets, news articles and papers that counter bad facts with good/accurate/honest ones. Don’t make stuff up (even a little). Validate your posits before publishing. Write said posts in a respectful tone.

Support the Media

When the POTUS’ Chief Strategist says things like “The media should be embarrassed and humiliated and keep its mouth shut and just listen for a while” it’s a deliberate attempt to curtail the Press and eventually there will be more actions to actually suppress Press freedom.

I’m not a liberal (I probably have no convenient definition) and I think the Press gave Obama a free ride during his eight year rule. They are definitely making up for that now, mostly because their very livelihoods are at stake.

The problem with them is that they are continuing to let themselves be manipulated by ?. He’s a master at this manipulation. Creating a story about the size of his hands in a picture delegitimizes you as a purveyor of news, especially when — as you’re watching his hands — he’s separating families, normalizing bigotry and undermining the Constitution. Forget about the hands and even forget about the hotels (for now). There was even a recent story trying to compare email servers (the comparison is very flawed). Stop it.

Encourage reporters to focus on things that actually matter and provide pointers to verifiable data they can use to call out the lack of veracity in ?’s policies. Personal blog posts are fleeting things but an NYT, WSJ (etc) story will live on.

Be Kind

I’ve heard and read some terrible language about rural America from what I can only classify as “liberals” in the week this post was written. Intellectual hubris and actual, visceral disdain for those who don’t think a certain way were two major reasons why ? got elected. The actual reasons he got elected are diverse and very nuanced.

Regardless of political leaning, pick your head up from your glowing rectangles and go out of your way to regularly talk to someone who doesn’t look, dress, think, eat, etc like you. Engage everyone with compassion. Regularly challenge your own beliefs.

There is a wedge that I estimate is about 1/8th of the way into the core of America now. Perpetuating this ideological “us vs them” mindset is only going to fuel the fires that created the conditions we’re in now and drive the wedge in further. The only way out is through compassion.

Remember: all life matters. Your degree, profession, bank balance or faith alignment doesn’t give you the right to believe you are better than anyone else.

FIN (for now)

I’ll probably move most of future opines to a new medium (not uppercase Medium) as you may be getting this drivel when you want recipes or R code (even though there are separate feeds for them).

Dear Leader has made good on his campaign promise to “crack down” on immigration from “dangerous” countries. I wanted to both see one side of the impact of that decree — how many potential immigrants per year might this be impacting — and show toss up some code that shows how to free data from PDF documents using the @rOpenSci tabulizer package — authored by (@thosjleeper) — (since knowing how to find, free and validate the veracity of U.S. gov data is kinda ++paramount now).

This is just one view and I encourage others to find, grab and blog other visa-related data and other government data in general.

So, the data is locked up in this PDF document:

As PDF documents go, it’s not horribad since the tables are fairly regular. But I’m not transcribing that and traditional PDF text extracting tools on the command-line or in R would also require writing more code than I have time for right now.

Enter: tabulizer — an R package that wraps tabula Java functions and makes them simple to use. I’m only showing one aspect of it here and you should check out the aforelinked tutorial to see all the features.

First, we need to setup our environment, download the PDF and extract the tables with tabulizer:

library(tabulizer)
library(hrbrmisc)
library(ggalt)
library(stringi)
library(tidyverse)

URL <- "https://travel.state.gov/content/dam/visas/Statistics/AnnualReports/FY2016AnnualReport/FY16AnnualReport-TableIII.pdf"
fil <- sprintf("%s", basename(URL))
if (!file.exists(fil)) download.file(URL, fil)

tabs <- tabulizer::extract_tables("FY16AnnualReport-TableIII.pdf")

You should str(tabs) in your R session. It found all our data, but put it into a list with 7 elements. You actually need to peruse this list to see where it mis-aligned columns. In the “old days”, reading this in and cleaning it up would have taken the form of splitting & replacing elements in character vectors. Now, after our inspection, we can exclude rows we don’t want, move columns around and get a nice tidy data frame with very little effort:

bind_rows(
  tbl_df(tabs[[1]][-1,]),
  tbl_df(tabs[[2]][-c(12,13),]),
  tbl_df(tabs[[3]][-c(7, 10:11), -2]),
  tbl_df(tabs[[4]][-21,]),
  tbl_df(tabs[[5]]),
  tbl_df(tabs[[6]][-c(6:7, 30:32),]),
  tbl_df(tabs[[7]][-c(11:12, 25:27),])
) %>%
  setNames(c("foreign_state", "immediate_relatives",  "special_mmigrants",
             "family_preference", "employment_preference", "diversity_immigrants","total")) %>% 
  mutate_each(funs(make_numeric), -foreign_state) %>%
  mutate(foreign_state=trimws(foreign_state)) -> total_visas_2016

I’ve cleaned up PDFs before and that code was a joy to write compared to previous efforts. No use of purrr since I was referencing the list structure in the console as I entered in the various matrix coordinates to edit out.

Finally, we can extract the target “bad” countries and see how many human beings could be impacted this year by referencing immigration stats for last year:

filter(foreign_state %in% c("Iran", "Iraq", "Libya", "Somalia", "Sudan", "Syria", "Yemen")) %>%
  gather(preference, value, -foreign_state) %>%
  mutate(preference=stri_replace_all_fixed(preference, "_", " " )) %>%
  mutate(preference=stri_trans_totitle(preference)) -> banned_visas

ggplot(banned_visas, aes(foreign_state, value)) +
  geom_col(width=0.65) +
  scale_y_continuous(expand=c(0,5), label=scales::comma) +
  facet_wrap(~preference, scales="free_y") +
  labs(x="# Visas", y=NULL, title="Immigrant Visas Issued (2016)",
       subtitle="By Foreign State of Chargeability or Place of Birth; Fiscal Year 2016; [Total n=31,804] — Note free Y scales",
       caption="Visa types explanation: https://travel.state.gov/content/visas/en/general/all-visa-categories.html\nSource: https://travel.state.gov/content/visas/en/law-and-policy/statistics/annual-reports/report-of-the-visa-office-2016.html") +
  theme_hrbrmstr_msc(grid="Y") +
  theme(axis.text=element_text(size=12))

~32,000 human beings potentially impacted, many who will remain separated from family (“family preference”); plus, the business impact of losing access to skilled labor (“employment preference”).

Go forth and find more US gov data to free (before it disappears)!

Preheat oven to 425°F

Pie:

  • 4 large eggs
  • 1 large can pumpkin (or steam & puree your own)
  • ¾ cup of brown sugar (dark brown preferable)
  • ¾ cup of cane sugar
  • 1 tablespoon ground cinnamon
  • 1 teaspoon ground cloves
  • 1 teaspoon ground ginger
  • ½ teaspoon fresh grated nutmeg
  • pinch of coarse sea salt or kosher salt
  • 18 oz coconut milk (that’s ~2 cans but not 2 full cans. save the rest for the ganache)

I’m not about to tell you how to make your fav pie crust as that’s a deeply personal subject. You’ll need two of them.

Mix the above well with a whisk. Put into two prepared pie crusts.

Bake at 425°F for 15 minutes. Turn oven to 350°F and bake 40-50 minutes. Remove and cool on wire rack for an hour or until totally cool.

Ganache:

  • 16 oz dark chocolate (cut into chip-sized chunks)
  • 1 cup of coconut milk
  • 1 teaspoon vanilla

Put prepared chocolate chips in a bowl.

Mix coconut milk and vanilla well and microwave for 1-2 minutes until violently frothing.

Pour over chocolate.

Wait 60-120 seconds.

Using a spatula, gently incorporate the coconut milk into the chocolate until blended.

When cool enough but still thin enough to pour, pour half over each pie. Swirl around by hand until covered. Refrigerate.

2021-11-04 UPDATE: Just use {arrow}.


Apache Drill is a nice tool to have in the toolbox as it provides a SQL front-end to a wide array of database and file back-ends and runs in standalone/embedded mode on every modern operating system (i.e. you can get started with or play locally with Drill w/o needing a Hadoop cluster but scale up almost effortlessly). It’s also a bit more lightweight than Spark and a nice alternative to Spark if you only need data wrangling and not the functionality in Spark’s MLlib.

When you’re in this larger-data world, parquet files are one of the core data storage formats. They’re designed to be compact and are optimized for columnar operations. Unlike CSV, JSON files or even R Data files, it’s not necessary to read or scan an entire parquet file to filter, select, aggregate, etc across columns. Unfortunately, parquet files aren’t first-class citizens in R. Well, they aren’t now, but thanks to this project it might not be too difficult to make an R interface to them. But, for now, you have to use some other means to convert or read parquet files.

Spark and sparklyr can help you write parquet files but I don’t need to run Spark all the time.

If you’re already a Drill user, you already know how easy it is to make parquet files with Drill:

CREATE TABLE dfs.tmp.sampleparquet AS 
  (SELECT trans_id, 
   cast(`date` AS date) transdate, 
   cast(`time` AS time) transtime, 
   cast(amount AS double) amountm,
   user_info, marketing_info, trans_info 
   FROM dfs.`/Users/drilluser/sample.json`);

If you’re not used to SQL, that may seem very ugly/foreign/verbose to you and you can thank Hadley for designing a better grammar of tidyness that seamlessly builds SQL queries like that behind the scenes for you. That SQL statement uses a JSON file as a data source (which you can do with Drill) make sure the field data types are correct by explicitly casting them to SQL data types (which is a good habit to get into even if it is verbose) and then tells Drill to make a parquet file (it’s actually a directory of parquet files) from it.

I’ve been working on an R package — sergeant — that provides RJDBC, direct REST and dplyr interfaces to Apache Drill for a while now. There are a number of complexities associated with creating a function to help users make parquet files from R data frames in Drill (which is why said function still does not exist in sergeant):

  • Is Drill installed or does there need to be a helper set of functions for installing and running Drill in embedded mode?
  • Even if there’s a Drill cluster running, does the user — perhaps — want to do the conversion locally in embedded mode? Embedded is way easier since all the files are local. The only real way to convert a data frame to Drill is to save a data frame to a temporary, interim file and them have Drill read it in. In a cluster mode where your local filesystem is not part of the cluster, that would mean finding the right way to get the file to the cluster. Which leads to the next item…
  • Where does the user want the necessary temporary files stored? Local dfs. file system? HDFS?
  • Do we need two different methods? One for quick conversion and one that forces explicit column data type casting?
  • Do we need to support giving the user explicit casting control and column selection capability?
  • Who put the bomp in the bomp, bomp, bomp?

OK, perhaps not that last one (but I think it still remains a mystery despite claims by Jan and Dean).

It’s difficult to wrap something like that up in a simple package that will make 80% of the possible user-base happy (having Drill and Spark operate behind the scenes like “magic” seems like a bad idea to me despite how well sparklyr masks the complexity).

As I continue to work that out (you are encouraged to file an issue with your opines on it at the gh repo) here’s a small R script that you can use it to turn R data frames into parquet files:

library(sergeant)
library(tidyverse)

# make a place to hold our temp files
# this is kinda super destructive. make sure you have the path right
unlink("/tmp/pqtrans", recursive=TRUE, force=TRUE)
dir.create("/tmp/pqtrans", showWarnings=FALSE)

# save off a large-ish tibble
write_csv(nycflights13::flights, "/tmp/pqtrans/flights.csvh")

# connect to drill
db <- src_drill("localhost")

# make the parquet file
dbGetQuery(db$con, "
CREATE TABLE dfs.tmp.`/pqtrans/flights.parquet` AS SELECT * FROM dfs.tmp.`/pqtrans/flights.csvh`
")
## # A tibble: 1 × 2
##   `Number of records written` Fragment
## *                       <int>    <chr>
## 1                      336776      0_0

# prove we did it
list.files("/tmp/pqtrans", recursive=TRUE, include.dirs=TRUE)
## [1] "flights.csvh"                  "flights.parquet"              
## [3] "flights.parquet/0_0_0.parquet"

# prove it again
flights <- tbl(db, "dfs.tmp.`/pqtrans/flights.parquet`")

flights
## Source:   query [?? x 19]
## Database: Drill 1.9.0 [localhost:8047] [8GB direct memory]
## 
##    flight arr_delay distance  year tailnum dep_time sched_dep_time origin
##     <int>     <dbl>    <dbl> <int>   <chr>    <int>          <int>  <chr>
## 1    1545        11     1400  2013  N14228      517            515    EWR
## 2    1714        20     1416  2013  N24211      533            529    LGA
## 3    1141        33     1089  2013  N619AA      542            540    JFK
## 4     725       -18     1576  2013  N804JB      544            545    JFK
## 5     461       -25      762  2013  N668DN      554            600    LGA
## 6    1696        12      719  2013  N39463      554            558    EWR
## 7     507        19     1065  2013  N516JB      555            600    EWR
## 8    5708       -14      229  2013  N829AS      557            600    LGA
## 9      79        -8      944  2013  N593JB      557            600    JFK
## 10    301         8      733  2013  N3ALAA      558            600    LGA
## # ... with more rows, and 11 more variables: sched_arr_time <int>,
## #   dep_delay <dbl>, dest <chr>, minute <dbl>, carrier <chr>, month <int>,
## #   hour <dbl>, arr_time <int>, air_time <dbl>, time_hour <dttm>,
## #   day <int>

# work with the drill parquet file
count(flights, year, origin) %>%
  collect()
## Source: local data frame [3 x 3]
## Groups: year [1]
## 
##    year origin      n
## * <int>  <chr>  <int>
## 1  2013    EWR 120835
## 2  2013    LGA 104662
## 3  2013    JFK 111279

That snippet:

  • assumes Drill is running, which is really as easy as entering drill-embedded at a shell prompt, but try out Drill in 10 Minutes if you don’t believe me
  • dfs.tmp points to /tmp (i.e. you need to modify that if yours doesn’t…see, I told you this wasn’t simple)
  • assumes we’re OK with letting Drill figure out column types
  • assumes we want ALL THE COLUMNS
  • uses the .csvh extension which tells Drill to read the column names from the first line so we don’t have to create the schema from scratch
  • is slow because of ↑ due to the need to create the csvh file first
  • exploits the fact that we can give dplyr the cold shoulder and talk directly to Drill anytime we feel like it with DBI calls by using the $con list field (the dbGetQuery(db$con, …) line).

It’s a naive and destructive snippet, but does provide a means to get your data frames into parquet and into Drill.

Most of my Drill parquet needs are converting ~20-100K JSON files a day into parquet, which is why I haven’t focused on making a nice interface for this particular use case (data frame to parquet) in R. Ultimately, I’ll likely go the “wrap parquet-cpp route” (unless you’re working on that, which — if you are — you should @-ref me in that gh-repo of yours so I can help out). But, if having a sergeant function to do this conversion would help you, drop an issue in the repo.

I had started a “52 Vis” initiative back in 2016 to encourage folks to get practice making visualizations since that’s the only way to get better at virtually anything. Life got crazy, 52 Vis fell to the wayside and now there are more visible alternatives such as Makeover Monday and Workout Wednesday. They’re geared towards the “T” crowd (I’m not giving a closed source and locked-in-data product any more marketing than two links) but that doesn’t mean R, Python or other open-tool/open-data communities can’t join in for the ride and learning experience.

This week’s workout is a challenge to reproduce or improve upon a chart by Matt Stiles. You should go to both (give them the clicks and eyeballs they both deserve since they did great work). They both chose a line chart, but the whole point of these exercises is to try out new things to help you learn how to communicate better. I chose to use geom_segment() to make mini-column charts since that:

  • eliminates the giant rose-coloured rectangles that end up everywhere
  • helps show the differences a bit better (IMO), and
  • also helps highlight some of the states that have had more difficulties than others

Click/tap to “embiggen”. I kept the same dimensions that Andy did but unlike Matt’s creation this is a plain ol’ PNG as I didn’t want to deal with web fonts (I’m on a Museo Sans Condensed kick at the moment but don’t have it in my TypeKit config yet). I went with official annual unemployment numbers as they may be calculated/adjusted differently (I didn’t check, but I knew that data source existed, so I used it).

One reason I’m doing this is a quote on the Workout Wednesday post:

This will be a very tedious exercise. To provide some context, this took me 2-3 hours to create. Don’t get discouraged and don’t feel like you have to do it all in one sitting. Basically, try to make yours look identical to mine.

This took me 10 minutes to create in R:

#' ---
#' output:
#'  html_document:
#'    keep_md: true
#' ---
#+ message=FALSE
library(ggplot2)
library(hrbrmisc)
library(readxl)
library(tidyverse)

# Use official BLS annual unemployment data vs manually calculating the average
# Source: https://data.bls.gov/timeseries/LNU04000000?years_option=all_years&periods_option=specific_periods&periods=Annual+Data
read_excel("~/Data/annual.xlsx", skip=10) %>%
  mutate(Year=as.character(as.integer(Year)), Annual=Annual/100) -> annual_rate


# The data source Andy Kriebel curated for you/us: https://1drv.ms/x/s!AhZVJtXF2-tD1UVEK7gYn2vN5Hxn #ty Andy!
read_excel("~/Data/staadata.xlsx") %>%
  left_join(annual_rate) %>%
  filter(State != "District of Columbia") %>%
  mutate(
    year = as.Date(sprintf("%s-01-01", Year)),
    pct = (Unemployed / `Civilian Labor Force Population`),
    us_diff = -(Annual-pct),
    col = ifelse(us_diff<0,
               "Better than U.S. National Average",
               "Worse than U.S. National Average")
  ) -> df

credits <- "Notes: Excludes the District of Columbia. 2016 figure represents October rate.\nData: U.S. Bureau of Labor Statistics <https://www.bls.gov/lau/staadata.txt>\nCredit: Matt Stiles/The Daily Viz <thedailyviz.com>"

#+ state_of_us, fig.height=21.5, fig.width=8.75, fig.retina=2
ggplot(df, aes(year, us_diff, group=State)) +
  geom_segment(aes(xend=year, yend=0, color=col), size=0.5) +
  scale_x_date(expand=c(0,0), date_labels="'%y") +
  scale_y_continuous(expand=c(0,0), label=scales::percent, limit=c(-0.09, 0.09)) +
  scale_color_manual(name=NULL, expand=c(0,0),
                     values=c(`Better than U.S. National Average`="#4575b4",
                              `Worse than U.S. National Average`="#d73027")) +
  facet_wrap(~State, ncol=5, scales="free_x") +
  labs(x=NULL, y=NULL, title="The State of U.S. Jobs: 1976-2016",
       subtitle="Percentage points below or above the national unemployment rate, by state. Negative values represent unemployment rates\nthat were lower — or better, from a jobs perspective — than the national rate.",
       caption=credits) +
  theme_hrbrmstr_msc(grid="Y", strip_text_size=9) +
  theme(panel.background=element_rect(color="#00000000", fill="#f0f0f055")) +
  theme(panel.spacing=unit(0.5, "lines")) +
  theme(plot.subtitle=element_text(family="MuseoSansCond-300")) +
  theme(legend.position="top")

Swap out ~/Data for where you stored the files.

The “weird” looking comments enable me to spin the script and is pretty much just the inverse markup for knitr R Markdown documents. As the comments say, you should really thank Andy for curating the BLS data for you/us.

If I really didn’t pine over aesthetics it would have taken me 5 minutes (most of that was waiting for re-rendering). Formatting the blog post took much longer. Plus, I can update the data source and re-run this in the future without clicking anything. This re-emphasizes a caution I tell my students: beware of dragon droppings (“drag-and-drop data science/visualization tools”).

Hopefully you presently follow or will start following Workout Wednesday and Makeover Monday and dedicate some time to hone your skills with those visualization katas.