Python Study Notes (6) abstraction (II)

6.4.5 reversal process

We have already discussed how to collect parameters as tuples and dictionaries. But in fact, if you use * and *, you can perform the opposite operation.

>>> def add(x,y): return x+y>>> params=(1,2)>>> add(*params)3

You can use the same technology to process dictionaries.

>>> def hello_3(greeting ='hello',name='world'):print '%s, %s'%(greeting,name)>>> params={'name':'daxiao','greeting':'i love'}>>> hello_3(**params)i love, daxiao

6.5 Scope

Like C, variables defined within a function are valid only within the function.

Read global variables:

>>> def combine(temp):print temp+temp2>>> temp2='b'>>> combine('a')ab

Change global variables

>>> x=1>>> def change():global xx+=1>>> change()>>> x2

6.6 Recursion

6.6.1 example

Fibonacci series:

ef f(i):if(i==1):return 1else:if(i==2):return 1else:return f(i-1)+f(i-2)

6.6.2 Binary Search

Omitted.

This chapter is relatively simple in general. After all, it is all the content you have learned before.

Summary

Abstraction

Function Definition

Parameters

Scope

Recursion

Function Programming