In pandas, is there any compact way to plot data across days of the week?
I have a simple framework with a set of values written against datetime
that are set to an index. Is there some compact way to get this data over several days of the week? I mean something like the following, the days of the week on the horizontal axis and the data for different weeks in different colors:
My current code looks like this, but it seems to be more difficult for a conceptually simple thing:
df["weekday"] = df["datetime"].dt.weekday
df["weekday_name"] = df["datetime"].dt.weekday_name
df["time_through_day"] = df["datetime"].map(lambda x: x - datetime.datetime.combine(x.date(), datetime.time()))
def days_through_week(row):
return row["weekday"] + row["time_through_day"] / (24 * np.timedelta64(1, "h"))
df["days_through_week"] = df.apply(lambda row: days_through_week(row), axis = 1)
datasets = []
dataset = []
previous_days_through_week = 0
for days_through_week, value in zip(df["days_through_week"], df["value"]):
if abs(days_through_week - previous_days_through_week) < 5:
dataset.append([days_through_week, value])
else:
datasets.append(dataset)
dataset = []
previous_days_through_week = days_through_week
for dataset in datasets:
x = [datum[0] for datum in dataset]
y = [datum[1] for datum in dataset]
plt.plot(x, y, linestyle = "-", linewidth = 1.3)
plt.ylabel("value")
plt.xticks(
[ 0.5, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5],
[ "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
)
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Setting:
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
np.random.seed(51723)
#Make some fake data to play with. Includes a partial week.
n = pd.DatetimeIndex(start="2-Jan-2017", end="1-Mar-2017", freq="1H")
df = pd.DataFrame(index=n, data=np.random.randn(n.size), columns=['A'])
df.A = df.groupby(df.index.week).A.transform('cumsum')
Plot:
#list of names for xtick labels. Extra Monday for end.
weekday_names = "Mon Tue Wed Thu Fri Sat Sun Mon".split(' ')
fig, ax = plt.subplots()
for name, group in df.groupby(df.index.week):
start_day= group.index.min().to_pydatetime()
#convert date to week age
Xs = mdates.date2num(group.index.to_pydatetime()) \
- mdates.date2num(start_day)
Ys = group.A
ax.plot(Xs, Ys)
ax.set_xticklabels(weekday_names)
ax.set_xticks(range(0, len(weekday_names)))
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