hi, I have some issues with my real time plotting for matplotlib. I am using "time" on the X axis and a random number on Y axis. The random number is a static number then multiplied by a random number
import matplotlib.pyplot as plt
import datetime
import numpy as np
import time
def GetRandomInt(Data):
timerCount=0
x=[]
y=[]
while timerCount < 5000:
NewNumber = Data * np.random.randomint(5)
x.append(datetime.datetime.now())
y.append(NewNumber)
plt.plot(x,y)
plt.show()
time.sleep(10)
a = 10
GetRandomInt(a)
This seems to crash python as it cannot handle the updates - I can add a delay but wanted to know if the code is doing the right thing? I have cleaned the code to do the same function as my code, so the idea is we have some static data, then some data which we want to update every 5 seconds or so and then to plot the updates. Thanks!
To draw a continuous set of random line plots, you would need to use animation in matplotlib:
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
fig, ax = plt.subplots()
max_x = 5
max_rand = 10
x = np.arange(0, max_x)
ax.set_ylim(0, max_rand)
line, = ax.plot(x, np.random.randint(0, max_rand, max_x))
def init(): # give a clean slate to start
line.set_ydata([np.nan] * len(x))
return line,
def animate(i): # update the y values (every 1000ms)
line.set_ydata(np.random.randint(0, max_rand, max_x))
return line,
ani = animation.FuncAnimation(
fig, animate, init_func=init, interval=1000, blit=True, save_count=10)
plt.show()
The idea here is that you have a graph containing x
and y
values. Where x
is just a range eg 0 to 5. You then call animation.FuncAnimation()
which tells matplotlib to call your animate()
function every 1000ms
to let you provide new y
values.
You can speed this up as much as you like by modifying the interval
parameter.
One possible approach if you wanted to plot values over time, you could use a deque()
to hold the y
values and then use the x
axis to hold seconds ago
:
from collections import deque
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
from matplotlib.ticker import FuncFormatter
def init():
line.set_ydata([np.nan] * len(x))
return line,
def animate(i):
# Add next value
data.append(np.random.randint(0, max_rand))
line.set_ydata(data)
plt.savefig('e:\\python temp\\fig_{:02}'.format(i))
print(i)
return line,
max_x = 10
max_rand = 5
data = deque(np.zeros(max_x), maxlen=max_x) # hold the last 10 values
x = np.arange(0, max_x)
fig, ax = plt.subplots()
ax.set_ylim(0, max_rand)
ax.set_xlim(0, max_x-1)
line, = ax.plot(x, np.random.randint(0, max_rand, max_x))
ax.xaxis.set_major_formatter(FuncFormatter(lambda x, pos: '{:.0f}s'.format(max_x - x - 1)))
plt.xlabel('Seconds ago')
ani = animation.FuncAnimation(
fig, animate, init_func=init, interval=1000, blit=True, save_count=10)
plt.show()
Giving you:
您实例化GetRandomInt,实例化PlotData,实例化GetRandomInt,实例化PlotData,...等等。这就是问题的根源。
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.