Python3入门教程 python3基础

# 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
'''    

# ! /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
     '''

# ! /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
'''

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.

'''
 

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))

s = input( " 输入你的中文名,按回车继续 " );
print  ( " 你的名字是  :  "   + s)

l = len(s)
print  ( " 你中文名字的长度是: " + str(l))