CODEWITHSUNDEEP
pythonmatplotlib
Jonny
Jonny

Reputation: 1378

Matplotlib even frequency binned by month bar chart

I want to create a bar chart where the x-axis represents months and the height of the bars are proportional to the amount of days entered into a list of dates that fall in this month. I want to dynamically update the list and the program should then update the graph as this list is extended.

I am able to create a list of dates as follows:

import matplotlib.pyplot as plt
import datetime

dates =  [datetime.date(2015,01,05),
          datetime.date(2015,01,18),
          datetime.date(2015,01,25),
          datetime.date(2015,02,18),
          datetime.date(2015,03,07),
          datetime.date(2015,03,27),]

If I run the script I would like to see something like:

enter image description here

Which I plotted here manually.

I know it will be possible to use a loop to run through the list of dates and manually sum the dates using if statements if the dates' months correspond etc. But I am hoping there is some more automated method in python/matplotlib.

Upvotes: 0

Views: 1825

Answers (1)

matt_s
matt_s

Reputation: 1075

You could use pandas for this:

import pandas as pd
import datetime

dates =  [datetime.date(2015,01,05),
          datetime.date(2015,01,18),
          datetime.date(2015,01,25),
          datetime.date(2015,02,18),
          datetime.date(2015,03,07),
          datetime.date(2015,03,27),]

df = pd.DataFrame({'dates':dates})
df.dates = pd.to_datetime(df.dates)

df.groupby(df.dates.dt.month).count().plot(kind='bar')

Gives:

enter image description here

The df.dates.dt.month is getting the month for each. You could group by day, year, etc, in the same way.

Upvotes: 2

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