matplotlib example plotLogfile (snippet)

Python matplotlib example 'plotLogfile'

Modules used in program:

import tkFileDialog
import sys
import matplotlib.cm as cm
import matplotlib.dates as mdates
import matplotlib.animation as animation
import matplotlib
import os
import random
import numpy as np

python plotLogfile

Python matplotlib example: plotLogfile

# Plot log files
# version 3
# Amar 
# Changes: v2: 2012/11/27: Date & time display using native matplotlib, instead of unix timestamp
#          v3: 2013/10/10: Rewritten completely using matplotlib animation, and slider for selectable range

import numpy as np
import random
import os
os.chdir("c:/data/googledrive/logs")
from datetime import datetime

import matplotlib
import matplotlib.animation as animation
from matplotlib.widgets import Slider, Button, RadioButtons
import matplotlib.dates as mdates
import matplotlib.cm as cm
matplotlib.use('TkAgg')
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg, NavigationToolbar2TkAgg
from matplotlib.figure import Figure

import sys
if sys.version_info[0] < 3:
    import Tkinter as Tk
else:
    import tkinter as Tk
import tkFileDialog

if __name__ == '__main__':
    root = Tk.Tk()
    try:
        filename = tkFileDialog.askopenfilename(parent=root,title='Choose file to plot')
        root.wm_title(filename)

        fig = Figure()
        ax = fig.add_subplot(111)
        ax.autoscale(enable=True)
        canvas = FigureCanvasTkAgg(fig, master=root)
        canvas.show()
        canvas.get_tk_widget().pack(side=Tk.TOP, fill=Tk.BOTH, expand=1)
        toolbar = NavigationToolbar2TkAgg( canvas, root )
        toolbar.update()
        canvas._tkcanvas.pack(side=Tk.TOP, fill=Tk.BOTH, expand=1)

        # For showing dates
        fig.autofmt_xdate()
        ax.fmt_xdata = mdates.DateFormatter('%Y-%m-%d %H:%M:%S')

        # Set titles and comments
        f = file(filename,'r')
        titleLine = f.readline()[2:]  # first line is the log comment 
        commentLine = f.readline()    # second line contains the column labels
        commentLine = commentLine[1:-1]
        comments = commentLine.split("\t")
        f.close()
        compactFileName = filename.split('/')[-1]
        ax.set_title(titleLine) 
        ax.set_ylabel(comments[1])

        axcolor = 'lightgoldenrodyellow'
        axNumber = fig.add_axes([0.25, 0.2, 0.65, 0.03],axisbg=axcolor)
        sNumber = Slider(axNumber, '# of pts', 1000, 10000, valfmt='%0.0f', valinit=5000)
        sNumber.valtext.set_visible(False)
        #sNumber.on_changed(duh)

        x0,y0 = np.loadtxt(filename,unpack=True)
        x0,y0 = x0[-sNumber.val::5],y0[-sNumber.val::5]
        x0 = map(datetime.fromtimestamp,x0)
        line, = ax.plot(x0,y0,linewidth=1.2,color = cm.spectral(random.randrange(0,255)))

        def update(dummyVar):
            try:
                x,y = np.loadtxt(filename,unpack=True) #np.random.rand(10),np.random.rand(10)
                x1,y1 = x[-sNumber.val::5],y[-sNumber.val::5]    
                yrange = max(y1) - min(y1)
                yavg = (max(y1) + min(y1))/2.
                ylims = yavg - 1.05*yrange/2., yavg + 1.05*yrange/2.

                ax.set_ylim(ylims[0],ylims[1])
                x1 = map(datetime.fromtimestamp,x1)
                ax.set_xlim(min(x1),max(x1))
                line.set_xdata(x1)
                line.set_ydata(y1)

            except ValueError or UnboundLocalError: pass
            return line,

        def data_gen():
            while True: yield True

        ani = animation.FuncAnimation(fig, update, data_gen, interval=3000)

    except IOError: pass

    Tk.mainloop()

Python links

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