app.py

import numpy as np
import pandas as pd
import plotly.express as px
import plotly.graph_objects as go
import plotly.io as pio
import streamlit as st

from datetime import datetime
from pprint import pprint

from scipy.stats import bootstrap


# Load data
with open('data.txt', 'r') as f:
  cases_data = f.readlines()

monthly_records = []
annual_records = []
for case_count in cases_data:
  data = case_count.split()

  # Annual data
  if len(data) == 2:
    data[1] = data[1].replace('(', '').replace(')', '')
    annual_records.append((int(data[0]), int(data[1])))
    continue

  # Monthly data
  data[2] = data[2].replace('(', '').replace(')', '')
  monthly_records.append((data[0], int(data[1]), int(data[2])))

pres_records = [
  ('Lyndon B. Johnson', datetime(1963, 11, 22), datetime(1969, 1, 20)),
  ('Richard Nixon', datetime(1969, 1, 20), datetime(1974, 8, 9)),
  ('Gerald Ford', datetime(1974, 8, 9), datetime(1977, 1, 20)),
  ('Jimmy Carter', datetime(1977, 1, 20), datetime(1981, 1, 20)),
  ('Ronald Reagan', datetime(1981, 1, 20), datetime(1989, 1, 20)),
  ('George H. W. Bush', datetime(1989, 1, 20), datetime(1993, 1, 20)),
  ('Bill Clinton', datetime(1993, 1, 20), datetime(2001, 1, 20)),
  ('George W. Bush', datetime(2001, 1, 20), datetime(2009, 1, 20)),
  ('Barack Obama', datetime(2009, 1, 20), datetime(2017, 1, 20)),
  ('Donald Trump', datetime(2017, 1, 20), datetime(2021, 1, 20)),
  ('Joe Biden', datetime(2021, 1, 20), datetime(2023, 6, 28))  # cut Biden short so that it lines up with our last data point
]
pres_df = pd.DataFrame.from_records(pres_records, columns=['name', 'start', 'end'])



# Clean the data

month2int = {
  'January': 1,
  'February': 2,
  'March': 3,
  'April': 4,
  'May': 5,
  'June': 6,
  'July': 7,
  'August': 8,
  'September': 9,
  'October': 10,
  'November': 11,
  'December': 12
}

mn_df = pd.DataFrame.from_records(monthly_records, columns=['month', 'year', 'cases'])

dts = []
for i, r in mn_df.iterrows():
  dts.append(datetime(year=r['year'], month=month2int[r['month']], day=28))

mn_df['date'] = dts

# This is the first year that has more than 1 case
clipped_mn_df = mn_df.query('year >= 1964')


# add 0s for months that are missing
# we cut off at 1964 but Johnson started in November of 1963
# There weren't any cases in 1963 so it's okay to start
# filling 0s from November of 1963
cur_yr = 1963
cur_mn = 11
new_rows = []

# pandas `in` is busted so we have to pull out the column manually
# and check against that
existing_dates = clipped_mn_df['date'].to_numpy(dtype=datetime)

# our data goes through the end of the previous month (june 2023)
# we're using 28 as the placeholder "day" for all the months
while cur_yr < 2023 or cur_mn <= 6:
  dt = datetime(year=cur_yr, month=cur_mn, day=28)
  if dt not in existing_dates:
    new_rows.append((dt.strftime('%B'), dt.year, 0, dt))

  if cur_mn == 12:
    cur_yr += 1
    cur_mn = 1
  else:
    cur_mn += 1

zero_rows = pd.DataFrame.from_records(new_rows, columns=['month', 'year', 'cases', 'date'])
clipped_mn_df = pd.concat([clipped_mn_df, zero_rows], ignore_index=True)
clipped_mn_df = clipped_mn_df.sort_values(by='date', ascending=False).reset_index(drop=True)


# add the mean & std for each president
presidents = []
for d in clipped_mn_df['date']:
  for i, r in pres_df.iterrows():
    if d >= r['start'] and d <= r['end']:
      presidents.append(str(r['name']))

clipped_mn_df['pres'] = presidents
tmp = clipped_mn_df[['cases', 'pres']].groupby('pres').agg(['mean', 'std']).reset_index(drop=False)
tmp.columns = ['name', 'cases_mean', 'cases_std']

pres_df = pd.merge(pres_df, tmp, on='name', how='inner')


# bootstrap confidence intervals for the mean
# the data doesn't really look normal enough for 2 std to be super meaningful
pres_names = pres_df['name'].unique()

president_cis = []
for pres in pres_names:
  cases = clipped_mn_df.query(f'pres == "{pres}"')['cases'].to_numpy()
  ci = bootstrap(
      cases.reshape(1,-1),
      np.mean,
      vectorized=False,
      confidence_level=0.95,
      method='BCa'  # "bias-corrected and accelerated" (shifts the CI bounds if the distribution is skewed)
  ).confidence_interval

  president_cis.append((pres, ci.low, ci.high))

ci_df = pd.DataFrame.from_records(president_cis, columns=['name', 'ci_low', 'ci_high'])

# add the confidence intervals to pres_df
pres_df = pd.merge(pres_df, ci_df, on='name')


# Utils for converting colors
def hex2rgb(h):
  """
  '#FF44BB' -> 'rgb(255, 68, 187)'
  """
  if h[0] == '#':
    h = h[1:]
  if len(h) != 6:
    raise ValueError(f'malformed hex input')
  values = []
  for i in range(0, len(h), 2):
    values.append(int(h[i:i+2], base=16))
  return f'rgb({values[0]}, {values[1]}, {values[2]})'

def rgb2rgba(c, a=1.0):
  """
  'rgb(95, 70, 144)'
  ->
  'rgba(95, 70, 144)'
  ->
  'rgba(95, 70, 144, 1.0)

  defaults to 100% opacity
  but you can set it
  """
  c = c[:3] + 'a' + c[3:]
  c = c[:-1] + f', {a})'
  return c


# Draw the plot

# streamlit ignores this but streamlit's theme
# is pure white so it's okay I guess?
pio.templates.default = 'plotly_white'

f = go.Figure()

FONT_SIZE = 14

# add the cases as a bar plot
bar_color = '#bbbbbb'
f.add_trace(go.Bar(
    x=clipped_mn_df['date'],
    y=clipped_mn_df['cases'],
    name='DOJ Antitrust Cases',
    marker_color=bar_color,
    marker_line_color=bar_color,
    hovertemplate='%{x}: <b>%{y}</b><extra></extra>',
    hoverlabel={'bgcolor': rgb2rgba(hex2rgb(bar_color), 0.2), 'font': {'size': FONT_SIZE}},
    legendrank=1000 + 1  # default is 1000. Bigger means closer to the top
))



# add the president means + CI
pres_colors = px.colors.qualitative.Prism

for i, r in pres_df.iterrows():
  # set up colors for this president
  pres_color = pres_colors[i]
  if pres_color[0] == '#':
    pres_color = hex2rgb(pres_color)

  ci_color = rgb2rgba(pres_color, 0.5)
  hover_color = rgb2rgba(pres_color, 0.2)

  hover_str = f"<b>{r['name']}</b><br>Mean: <b>{r['cases_mean']:.2f}</b><br>95% CI: <b>({r['ci_low']:.2f}–{r['ci_high']:.2f})</b><extra></extra>"
  hover_label_fmt = {'bgcolor': hover_color, 'font': {'size': FONT_SIZE}}


  # add this president's confidence interval
  #
  # draw two lines like this
  #
  # o------------------o
  #
  # o------------------o
  #
  # make the lines transparent,
  # fill in the area between them
  upper = r['ci_high']
  lower = r['ci_low']
  f.add_trace(go.Scatter(
    x = [r['start'], r['end'], r['end'], r['start']],
    y = [upper, upper, lower, lower],
    fill='toself',
    fillcolor=ci_color,
    line_color=rgb2rgba(pres_color, 0),
    # I have to set `name` for it to show up when I hover over any part of the fill
    # otherwise the hover only comes up when I hover over the corners where the points are
    # but `name` doesn't do the <extra></extra> thing to remove the extra hover box
    name=hover_str.replace('<extra></extra>',''),
    showlegend=False,
    hovertemplate=hover_str,
    hoverlabel=hover_label_fmt
  ))

  # add this president's mean
  f.add_trace(go.Scatter(
    x=[r['start'], r['end']],
    y=[r['cases_mean'],r['cases_mean']],
    name=r['name'],
    line_color=pres_color,
    # I used to have vertical bars at the ends of the mean line
    # but I like it more without them
    # so just set the width to 0
    marker={'symbol': 'line-ns', 'line': {'width': 0, 'color':pres_color}},
    hovertemplate=hover_str,
    hoverlabel=hover_label_fmt
  ))


# Trim the top of the plot a bit because there are a few outliers
# that make it hard to see the president aggregations
MAX_HEIGHT = 16
f.update_yaxes(range=[0, MAX_HEIGHT])

# add hashing over any bars taller than MAX_HEIGHT
# since we're cutting them off
too_tall = clipped_mn_df[clipped_mn_df['cases'] > MAX_HEIGHT]['date']
f.add_trace(go.Bar(
    x=too_tall,
    y=[MAX_HEIGHT * 0.25] * len(too_tall),
    base = [MAX_HEIGHT - MAX_HEIGHT*0.1] * len(too_tall),
    marker_color='#fff',
    marker_line_color='rgba(255,255,255,0)',
    marker_line_width=0,
    # I think I remember plotly uses milliseconds if the axis is a datetime
    # so the width has to be huge to cover a whole month
    # yep 1 month is 2.6 * 10**9 milliseconds
    width=3e9,
    # these are the options ['', '/', '\\', 'x', '-', '|', '+', '.']
    marker_pattern_shape='-',
    marker_pattern_fillmode='replace',
    showlegend=False
))
f.update_layout(barmode='stack')

f.update_layout(title="<b>What does the DOJ's Antitrust Division look like?</b>")

# since streamlit doesn't respect the Plotly theme,
# we can instead make the background transparent
f.update_layout({
'plot_bgcolor': 'rgba(0, 0, 0, 0)',
'paper_bgcolor': 'rgba(0, 0, 0, 0)',
})

st.set_page_config(layout='wide')
st.plotly_chart(f, use_container_width=True, theme=None)

col1, col2, col3 = st.columns(3)
col2.markdown("""
# The data

To get the data, I went to [the website for the Antitrust Division of the U.S. Department of Justice](https://www.justice.gov/atr/antitrust-case-filings), clicked "Filter by Case Open Date" in the left menu, and clicked "Show more." That gave me a pretty clean list that I could highlight and copy.

```
June 2023 (2)

April 2023 (1)

March 2023 (1)

February 2023 (2)

January 2023 (5)

2023 (11)

November 2022 (4)
[ . . . ]
```

There are some obvious problems with this data.
For example, I found [a Wikipedia article about U.S. antitrust law](https://en.wikipedia.org/wiki/United_States_antitrust_law).
That page refers to a case that happened in 1943, but my data doesn't have any cases in 1943.
I looked up the case (American Medical Association v. United States, 317 U.S. 519 (1943)) to see what the deal was.
I think that case, like the current case against Meta, was filed by the FTC—not the DOJ.
So this data is definitely not a complete record of U.S. antitrust cases.

There's also at least one typo in this random menu on the DOJ's website.
For the annual count of all cases opened in 2022, they list the correct amount but they label it "2026" instead.
I didn't notice any other typos.
I'm sure there are a few I missed.

That being said, this data is more than good enough for my goal.
I just want to vaguely describe the trend of antitrust cases with a pretty plot.
""")