An example of the perceptron algorithm

perceptron.py

samples = [[1,2], [2,0], [3,1], [2,2]]
labels = [1,1,-1,-1]

def dot(a, b):
    return sum([a[j]*b[j] for j in range(len(a))])

w, b = [0,0], 0

for n in range(100):
    n_updates = 0
    for i in range(len(labels)):
        x, y = samples[i], labels[i]
        if y*(dot(w, x) + b) <= 0:
            w = [w[j] + y*x[j] for j in range(len(w))]
            b = b + y
            n_updates = n_updates + 1
    if n_updates == 0: break

print(w, b)