day_of_week.py

import pandas as pd
from nltk.sentiment.vader import SentimentIntensityAnalyzer
from matplotlib import pyplot as plt

with open('tweets.csv') as tweets:
    df = pd.read_csv(tweets)

data = []
sid = SentimentIntensityAnalyzer()
df['timestamp'] = pd.to_datetime(df['timestamp'])
df['weekday'] = df['timestamp'].apply(lambda x: x.weekday())
chart = []
for (sentence, id) in zip(df.text.values, df.weekday.values):
    ss = sid.polarity_scores(sentence)
    chart.append({'sentiment': ss['compound'], 'date': id})


df = pd.DataFrame.from_records(chart)

mean_weekday = df.groupby('date')['sentiment'].mean()

fig, ax = plt.subplots()
plt.bar([0,1,2,3,4,5,6], mean_weekday)

ax.set_xticklabels(('M', 'T', 'W', 'T', 'F', 'S', 'S'))
plt.show()