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matplotlib.axes.Axes.get_xlim
Axes.get_xlim()- 
    
Get the x-axis range
Returns: xlimits : tuple
Returns the current x-axis limits as the tuple (
left,right).Notes
The x-axis may be inverted, in which case the
leftvalue will be greater than therightvalue. 
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 http://matplotlib.org/2.0.2/api/_as_gen/matplotlib.axes.Axes.get_xlim.html