Plotting for DataFrames

Question:

Plotting with DataFrames

Just like Pandas Series, DataFrames also have a plot() method. If df is a DataFrame, then df.plot() will produce a line plot with a different colored line for each variable in the DataFrame. This can be a convenient way to get a quick look at your data, especially for small DataFrames, but for more complicated plots you will usually want to use matplotlib directly.

In the following quiz, create a plot of your choice showing something interesting about the New York subway data. For example, you might create:

Histograms of subway ridership on both days with rain and days without rain
A scatterplot of subway stations with latitude and longitude as the x and y axes and ridership as the bubble size
- If you choose this option, you may wish to use the as_index=False argument to groupby(). There is example code in the following quiz.
A scatterplot with subway ridership on one axis and precipitation or temperature on the other

If you're not sure how to make the plot you want, try searching on Google or take a look at the matplotlib documentation. Once you've created a plot you're happy with, share what you've found on the forums!

Start Quiz:

plotting.py

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import seaborn as sns

values = np.array([1, 3, 2, 4, 1, 6, 4])
example_df = pd.DataFrame({
    'value': values,
    'even': values % 2 == 0,
    'above_three': values > 3 
}, index=['a', 'b', 'c', 'd', 'e', 'f', 'g'])

# Change False to True for this block of code to see what it does

# groupby() without as_index
if False:
    first_even = example_df.groupby('even').first()
    print first_even
    print first_even['even'] # Causes an error. 'even' is no longer a column in the DataFrame
    
# groupby() with as_index=False
if False:
    first_even = example_df.groupby('even', as_index=False).first()
    print first_even
    print first_even['even'] # Now 'even' is still a column in the DataFrame

filename = '/datasets/ud170/subway/nyc_subway_weather.csv'
subway_df = pd.read_csv(filename)

## Make a plot of your choice here showing something interesting about the subway data.
## Matplotlib documentation here: http://matplotlib.org/api/pyplot_api.html
## Once you've got something you're happy with, share it on the forums!

Solution: