本文适合有Java编程经验的程序员快速熟悉Python
本文程序在windows xp+python3.1a1 测试通过.
本文提到的idle指python shell,即安装python后你在菜单看到的IDLE(python gui)
在idle里ctrl+n可以打开一个新窗口,输入源码后ctrl+s可以保存,f5运行程序.
凡打开新窗口即指ctrl+n的操作.
1 你好
#打开新窗口,输入:
#! /usr/bin/python
# -*- coding: utf8 -*-
s1=input("Input your name:")
print("你好,%s" % s1)
'''
知识点:
* input("某字符串")函数:显示"某字符串",并等待用户输入.
* print()函数:如何打印.
* 如何应用中文
* 如何用多行注释
'''
2 字符串和数字
但有趣的是,在javascript里我们会理想当然的将字符串和数字连接,因为是动态语言嘛.但在Python里有点诡异,如下:
#! /usr/bin/python
a=2
b="test"
c=a+b
运行这行程序会出错,提示你字符串和数字不能连接,于是只好用内置函数进行转换
#! /usr/bin/python
#运行这行程序会出错,提示你字符串和数字不能连接,于是只好用内置函数进行转换
a=2
b="test"
c=str(a)+b
d="1111"
e=a+int(d)
#How to print multiply values
print ("c is %s,e is %i" % (c,e))
'''
知识点:
* 用int和str函数将字符串和数字进行转换
* 打印以#开头,而不是习惯的//
* 打印多个参数的方式
'''
3 列表
#! /usr/bin/python
# -*- coding: utf8 -*-
#列表类似Javascript的数组,方便易用
#定义元组
word=['a','b','c','d','e','f','g']
#如何通过索引访问元组里的元素
a=word[2]
print ("a is: "+a)
b=word[1:3]
print ("b is: ")
print (b) # index 1 and 2 elements of word.
c=word[:2]
print ("c is: ")
print (c) # index 0 and 1 elements of word.
d=word[0:]
print ("d is: ")
print (d) # All elements of word.
#元组可以合并
e=word[:2]+word[2:]
print ("e is: ")
print (e) # All elements of word.
f=word[-1]
print ("f is: ")
print (f) # The last elements of word.
g=word[-4:-2]
print ("g is: ")
print (g) # index 3 and 4 elements of word.
h=word[-2:]
print ("h is: ")
print (h) # The last two elements.
i=word[:-2]
print ("i is: ")
print (i) # Everything except the last two characters
l=len(word)
print ("Length of word is: "+ str(l))
print ("Adds new element")
word.append('h')
print (word)
#删除元素
del word[0]
print (word)
del word[1:3]
print (word)
'''
知识点:
* 列表长度是动态的,可任意添加删除元素.
* 用索引可以很方便访问元素,甚至返回一个子列表
* 更多方法请参考Python的文档
'''
4 字典
#! /usr/bin/python
x={'a':'aaa','b':'bbb','c':12}
print (x['a'])
print (x['b'])
print (x['c'])
for key in x:
print ("Key is %s and value is %s" % (key,x[key]))
'''
知识点:
* 将他当Java的Map来用即可.
'''
5 字符串
比起C/C++,Python处理字符串的方式实在太让人感动了.把字符串当列表来用吧.
#! /usr/bin/python
word="abcdefg"
a=word[2]
print ("a is: "+a)
b=word[1:3]
print ("b is: "+b) # index 1 and 2 elements of word.
c=word[:2]
print ("c is: "+c) # index 0 and 1 elements of word.
d=word[0:]
print ("d is: "+d) # All elements of word.
e=word[:2]+word[2:]
print ("e is: "+e) # All elements of word.
f=word[-1]
print ("f is: "+f) # The last elements of word.
g=word[-4:-2]
print ("g is: "+g) # index 3 and 4 elements of word.
h=word[-2:]
print ("h is: "+h) # The last two elements.
i=word[:-2]
print ("i is: "+i) # Everything except the last two characters
l=len(word)
print ("Length of word is: "+ str(l))
中文和英文的字符串长度是否一样?
#! /usr/bin/python
# -*- coding: utf8 -*-
s=input("输入你的中文名,按回车继续");
print ("你的名字是 : " +s) | 
转播
