Plotting time in Python with Matplotlib

Question

I have an array of timestamps in the format  HH MM SS mmmmmm  and another array of floating point numbers  each corresponding to a value in the timestamp array   Can I plot time on the x axis and the numbers on the y-axis using Matplotlib   I was trying to  but somehow it was only accepting arrays of floats  How can I get it to plot the time  Do I have to modify the format in any way

User · Answer

7 years later and this code has helped me. However, my times still were not showing up correctly.

Using Matplotlib 2.0.0 and I had to add the following bit of code from Editing the date formatting of x-axis tick labels in matplotlib by Paul H.

import matplotlib.dates as mdates
myFmt = mdates.DateFormatter('%d')
ax.xaxis.set_major_formatter(myFmt)

I changed the format to (%H:%M) and the time displayed correctly.

All thanks to the community.

User · Answer

You must first convert your timestamps to Python datetime objects  use datetime strptime   Then use date2num to convert the dates to matplotlib format   Plot the dates and values using plot date   dates   matplotlib dates date2num list of datetimes  matplotlib pyplot plot date dates  values

User · Answer

You can also plot the timestamp  value pairs using pyplot plot  after parsing them from their string representation    Tested with matplotlib versions 1 2 0 and 1 3 1    Example   import datetime import random import matplotlib pyplot as plt    make up some data x    datetime datetime now     datetime timedelta hours i  for i in range 12   y    i random gauss 0 1  for i   in enumerate x      plot plt plot x y    beautify the x-labels plt gcf   autofmt xdate    plt show     Resulting image       Here s the same as a scatter plot   import datetime import random import matplotlib pyplot as plt    make up some data x    datetime datetime now     datetime timedelta hours i  for i in range 12   y    i random gauss 0 1  for i   in enumerate x      plot plt scatter x y    beautify the x-labels plt gcf   autofmt xdate    plt show     Produces an image similar to this

User · Answer

I had trouble with this using matplotlib version  2 0 2  Running the example from above I got a centered stacked set of bubbles      I  fixed  the problem by adding another line   plt plot          The entire code snippet becomes   import datetime import random import matplotlib pyplot as plt import matplotlib dates as mdates     make up some data x    datetime datetime now     datetime timedelta minutes i  for i in range 12   y    i random gauss 0 1  for i   in enumerate x      plot plt plot        plt scatter x y     beautify the x-labels plt gcf   autofmt xdate   myFmt   mdates DateFormatter   H  M   plt gca   xaxis set major formatter myFmt   plt show   plt close     This produces an image with the bubbles distributed as desired

[python] Plotting time in Python with Matplotlib

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