Functions

def surface(w,h):
  print "calculating the surface by multiplying two input values"
  return w*h

# call the function
print surface(4,5)

Multiple return values

In Python, a function can return multiple values in one call.

def multireturn(x):
  return x, x+2, x+4

print multireturn(5)

The return value is actually an array:

def multireturn(x):
  return x, x+2, x+4

y=multireturn(20)

print y[0]
print y[1]
print y[2]

default parameters

Specify a default value:

def foo(a,b=5):
  bar