Q:

Plot Piecewise Function in Python

I would like to plot the following piecewise function in Python using Matplotlib, from 0 to 5.
f(x) = 1, x != 2; f(x) = 0, x = 2
In Python...
def f(x):
 if(x == 2): return 0
 else: return 1

Using NumPy I create an array 
x = np.arange(0., 5., 0.2)

    array([ 0. ,  0.2,  0.4,  0.6,  0.8,  1. ,  1.2,  1.4,  1.6,  1.8,  2. ,
        2.2,  2.4,  2.6,  2.8,  3. ,  3.2,  3.4,  3.6,  3.8,  4. ,  4.2,
        4.4,  4.6,  4.8])

I have tried things like...
import matplotlib.pyplot as plt
plt.plot(x,f(x))

Or...
vecfunc = np.vectorize(f)
result = vecfunc(t)

Or...
def piecewise(x):
 if x == 2: return 0
 else: return 1

import matplotlib.pyplot as plt
x = np.arange(0., 5., 0.2)
plt.plot(x, map(piecewise, x))

ValueError: x and y must have same first dimension

But I am not using these functions correctly, and am now just randomly guessing how to do this. 
Some answers are starting to get there... But the points are being connected into a line on the plot. How do we just plot the points?

A:

The problem is that the function f does not take an array as input but a single numer. You can:
plt.plot(x, map(f, x))

The map function takes a function f, an array x and returns another array where the function f is applied to each element of the array.

A:

Some answers are starting to get there... But the points are being
  connected into a line on the plot. How do we just plot the points?

import matplotlib.pyplot as plt
import numpy as np

def f(x):
 if(x == 2): return 0
 else: return 1

x = np.arange(0., 5., 0.2)

y = []
for i in range(len(x)):
   y.append(f(x[i]))

print x
print y

plt.plot(x,y,c='red', ls='', ms=5, marker='.')
ax = plt.gca()
ax.set_ylim([-1, 2])

plt.show()

