Use Line2D to plot line in python

You should add the line to a plot and then show it:

In [13]: import matplotlib.pyplot as plt

In [15]: from matplotlib.lines import Line2D      

In [16]: fig = plt.figure()

In [17]: ax = fig.add_subplot(111)

In [18]: x = [10,24,23,23,3]

In [19]: y = [12,2,3,4,2]

In [20]: line = Line2D(x, y)

In [21]: ax.add_line(line)
Out[21]: <matplotlib.lines.Line2D at 0x7f4c10732f60>

In [22]: ax.set_xlim(min(x), max(x))
Out[22]: (3, 24)

In [23]: ax.set_ylim(min(y), max(y))
Out[23]: (2, 12)

In [24]: plt.show()

The result:

The more common approach (not exactly what the questioner asked) is to use the plot interface. This involves Line2D behind the scenes.

>>> x = [10,24,23,23,3]
>>> y = [12,2,3,4,2]
>>> import matplotlib.pyplot as plt
>>> plt.plot(x,y)
[<matplotlib.lines.Line2D object at 0x7f407c1a8ef0>]
>>> plt.show()