Date formatting with matplotlib

Question

Using Python 2.6.2 Matplotlib 1.1.0 Based on http://matplotlib.sourceforge.net/examples/api/date_index_formatter.html, I have built a Python program to generate an image plot ``` gr = getResults() AttributeName = gr.getAttributeName(attributeId) dates = [] values = [] for data in gr.byClient(clientId, attributeId): dates.append(data[0]) values.append(data[1]) from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas from matplotlib.figure import Figure import matplotlib.ticker as ticker import numpy as np # Create a figure with size 6 x 6 inches. fig = Figure(figsize=(6,6)) # Create a canvas and add the figure to it. canvas = FigureCanvas(fig) # Create a subplot. ax = fig.add_subplot(111) # Set the title. ax.set_title("Response over time",fontsize=14) # Set the X Axis label. ax.set_xlabel("Date",fontsize=12) # Set the Y Axis label. ax.set_ylabel(AttributeName,fontsize=12) # Display Grid. ax.grid(True,linestyle='-',color='0.75') N = len(dates) ind = np.arange(N) def f…

Accepted Answer

You can call pylab.num2date() to convert this numbers into datetime object:

```
import pylab as pl
from matplotlib import ticker
from datetime import date

dates = [date(2012,7,10), date(2012,8,5), date(2012,9,4)]
values = [1,2,3]

def format_date(x, pos=None):
    return pl.num2date(x).strftime('%Y-%m-%d')

gca().xaxis.set_major_formatter(ticker.FuncFormatter(format_date))

# Generate the Scatter Plot.
scatter(dates,values,s=20,color='tomato');
gcf().autofmt_xdate()
```

Date formatting with matplotlib

Solution

Problem