Total and marginal distribution trips between neighborhoods

Let's focus our attention now the following important questions:

• Between which neighborhoods do the most common trips occur?
• Assuming that a traveler leaves from a given neighborhood, which neighborhoods are they most likely to go to?
• Assuming that someone was just dropped off at a given neighborhood, which neighborhoods are they most likely to have come from?

To answer the above questions, we need to find the distribution (or proportion) of trips between any two neighborhoods, first as a percentage of total trips, then as a percentage of trips leaving from a particular neighborhood, and finally as a percentage of trips going to a particular neighborhood.

rxc <- rxCube( ~ pickup_nb:dropoff_nb, mht_xdf)
rxc <- as.data.frame(rxc)

library(dplyr)
rxc %>% 
  filter(Counts > 0) %>%
  mutate(pct_all = Counts/sum(Counts) * 100) %>%
  group_by(pickup_nb) %>%
  mutate(pct_by_pickup_nb = Counts/sum(Counts) * 100) %>%
  group_by(dropoff_nb) %>%
  mutate(pct_by_dropoff_nb = Counts/sum(Counts) * 100) %>%
  group_by() %>%
  arrange(desc(Counts)) -> rxcs

head(rxcs)

# A tibble: 6 × 6
         pickup_nb      dropoff_nb  Counts  pct_all pct_by_pickup_nb
            <fctr>          <fctr>   <dbl>    <dbl>            <dbl>
1  Upper East Side Upper East Side 3299324 5.738650         36.88840
2          Midtown         Midtown 2216184 3.854700         21.84268
3  Upper West Side Upper West Side 1924205 3.346849         35.14494
4          Midtown Upper East Side 1646843 2.864422         16.23127
5  Upper East Side         Midtown 1607925 2.796730         17.97756
6 Garment District         Midtown 1072732 1.865847         28.94205
  pct_by_dropoff_nb
              <dbl>
1          38.28066
2          22.41298
3          35.15770
4          19.10762
5          16.26146
6          10.84888

Based on the first row, we can see that trips from the Upper East Side to the Upper East Side make up about 5% of all trips in Manhattan. Of all the trips that pick up in the Upper East Side, about 36% drop off in the Upper East Side. Of all the trips that drop off in the Upper East Side, 37% and tripped that also picked up in the Upper East Side.