程序代码：

# Returning functions from functions

# A simple function
def say_hello(greeter, greeted):
  return "Hello, " + greeted + ", I'm " + greeter + "."

# We can use it like this:
print say_hello("Alice", "Bob") # Displays "Hello, Bob, I'm Alice."

# We can also use it in a function:
def produce_greeting_from_alice(greeted):
  return say_hello("Alice", greeted)

print produce_greeting_from_alice("Bob") # Displays "Hello, Bob, I'm Alice."

# We can also return a function from a function by nesting them:
def produce_greeting_from(greeter):
  def greet(greeted):
    return say_hello(greeter, greeted)
  return greet

# Here we create a greeting function for Eve:
produce_greeting_from_eve = produce_greeting_from("Eve")//这里能理解为C中#define produce_greeting_from_eve  produce_greeting_from("Eve") 么？
# 'produce_greeting_from_eve' is now a function:
print produce_greeting_from_eve("Alice") # Displays "Hello, Alice, I'm Eve."

# You can also invoke the function directly if you want:
print produce_greeting_from("Bob")("Eve") # Displays "Hello, Eve, I'm Bob."

程序代码：

# Using functions in a dictionary instead of long if statements:

# Let's say we have a variable called 'current_action' and we want stuff to happen based on its value:

if current_action == 'PAUSE':
  pause()
elif current_action == 'RESTART':
  restart()
elif current_action == 'RESUME':
  resume()

# This can get long and complicated if there are many values.
# Instead, we can use a dictionary:

response_dict = {
  'PAUSE': pause,
  'RESTART': restart,
  'RESUME': resume
}

response_dict[current_action]() # Gets the correct function from response_dict and calls it//好屌，字符加个括号就成了同名函数了啊！