This year we celebrated Mega Pi Day with the date (3/14/15) covering the firstfourdigits of Pi. And of course, we unveiled the Pi Cake at 9:26 to get the next three digits. This year the cake came from Empire Cakes and was peanut butter flavored. We even had the bakery put as many digits as would fit around the cake.
However, he wondered if the preponderance of dollar slice shops has dropped the price of a slice below that of the subway and playfully joked that he wished there was a statistician in the audience.
Naturally, that night I set off to calculate the current price of a slice in New York City using listings from MenuPages. I used R’sXML package to pull the menus for over 1,800 places tagged as “Pizza” in Manhattan, Brooklyn and Queens (there was no data for Staten Island or The Bronx) and find the price of a cheese slice.
After cleaning up the data and doing my best to find prices for just cheese/plain/regular slices I found that the mean price was $2.33 with a standard deviation of $0.52 and a median price of $2.45. The base subway fare is $2.50 but is actually $2.38 after the 5% bonus for putting at least $5 on a MetroCard.
So, even with the proliferation of dollar slice joints, the average slice of pizza ($2.33) lines up pretty nicely with the cost of a subway ride ($2.38).
Taking it a step further, I broke down the price of a slice in Manhattan, Queens and Brooklyn. The vertical lines represented the price of a subway ride with and without the bonus. We see that the price of a slice in Manhattan is perfectly right there with the subway fare.
MenuPages even broke down Queens Neighborhoods so we can have a more specific plot.
The code for downloading the menus and the calculations is after the break.
## polla_qid Answer Votes pollq_id Question
## 1 2 Excellent 0 2 How was Pizza Mercato?
## 2 2 Good 6 2 How was Pizza Mercato?
## 3 2 Average 4 2 How was Pizza Mercato?
## 4 2 Poor 1 2 How was Pizza Mercato?
## 5 2 Never Again 2 2 How was Pizza Mercato?
## 6 3 Excellent 1 3 How was Maffei's Pizza?
## Place Time TotalVotes Percent
## 1 Pizza Mercato 1.344e+09 13 0.0000
## 2 Pizza Mercato 1.344e+09 13 0.4615
## 3 Pizza Mercato 1.344e+09 13 0.3077
## 4 Pizza Mercato 1.344e+09 13 0.0769
## 5 Pizza Mercato 1.344e+09 13 0.1538
## 6 Maffei's Pizza 1.348e+09 7 0.1429
ggplot(pizza, aes(x = Place, y = Percent, group = Answer, color = Answer)) +
geom_line() + theme(axis.text.x = element_text(angle = 46, hjust = 1), legend.position = "bottom") +
labs(x = "Pizza Place", title = "Pizza Poll Results")
But given this is live data that will change as more polls are added I thought it best to use a plot that automatically updates and is interactive. So this gave me my first chance to needrCharts by Ramnath Vaidyanathan as seen at October’s meetup.
There are still a lot of things I am learning, including how to use a categorical x-axis natively on linecharts and inserting chart titles. I found a workaround for the categorical x-axis by using tickFormat but that is not pretty. I also would like to find a way to quickly switch between a line chart and a bar chart. Fitting more labels onto the x-axis or perhaps adding a scroll bar would be nice too.
As mentioned earlier, yesterday was Pi Day so a bunch of statisticians and other such nerds celebrated at the new(ish) Artichoke Basille near the High Line. We had three pies: the signature Artichoke, the Margherita and the Anchovy, which was delicious but only some of us ate. And of course we had our custom cake from Chrissie Cook.
It gets really interesting when he says, “You know these deep-dish pizzas—it’s not pizza. It’s very good, but … call it tomato pie or something.” While an argument can certainly me made that deep-dish pizza is almost a casserole, I think the folks down in Trenton (where Scalia was born) have already claimed the name tomato pie, referring to a round pie with the sauce on top.