I want to make a plot with matplotlib, that looks like this:
The problem is I am getting the data from mySQL and the date is a string therefore. I want to assign a date to each y-value. The current date format is like that: Y-M-d h:m:s
Can you help me with how I must format this into a valid datetime, or is it possible to plot strings on x-axis and float on y-axis?
It is normally best to first convert your data to datetime format. It can then be formatted using a DateFormatter as follows:
import matplotlib
import matplotlib.pyplot as plt
from datetime import datetime
x_orig = ['2015-12-29 15:01:25', '2015-12-29 15:02:08', '2015-12-29 15:02:13', '2015-12-29 15:04:18']
x = [datetime.strptime(d, '%Y-%m-%d %H:%M:%S') for d in x_orig]
y = ['7.1', '7.4', '9.4', '10.2']
xs = matplotlib.dates.date2num(x)
hfmt = matplotlib.dates.DateFormatter('%Y-%m-%d\n%H:%M:%S')
fig = plt.figure()
ax = fig.add_subplot(1,1,1)
ax.patch.set_facecolor('lightgrey')
ax.xaxis.set_major_formatter(hfmt)
ax.set_title('Titel des Reports')
ax.set_xlabel('datum')
ax.set_ylabel('2MTemperatur')
plt.setp(ax.get_xticklabels(), size=8)
ax.plot(xs, y, linewidth=2)
ax.scatter(xs, y)
plt.grid()
plt.show()
This would give you the following:
