Python的基础语法（二）

Tuple数据类型：

mixed_tuple = (1 , 2, ['a','b'])
print("mixed_tuple:" + str(mixed_tuple))
mixed_tuple[2][0]='c'
mixed_tuple[2][1]='d'
print("mixed_tuple after:" + str(mixed_tuple))

　　字典的应用：

# coding: utf-8

# 创建一个词典
phone_book= {'Tom':123,'sunliyuan':456,'shi':789}

mixed_dict={"Tom":'boy',11:23.5}

# 字典的调用
print ("sunliyuan has phone numbr:"+  str(phone_book["sunliyuan"]))

# 修改字典的值
phone_book['sunliyuan']=521
print ("sunliyuan has phone numbr:"+  str(phone_book["sunliyuan"]))

# 添加一个值
phone_book['sunli']=888
print ("sunliyuan has phone numbr:"+  str(phone_book))

# 删除字典中的元素和本身
del phone_book['sunli']
print ("sunli after del is:"+  str(phone_book))

# 清空字典的值
phone_book.clear()
print ("sunli after del is:"+  str(phone_book))

# 清空字典本身
del phone_book
print ("sunli after del is:"+  str(phone_book))

　　运行的效果图：

# 特性
# 不允许同一个键出现两次
rep_test={'Name':'aa','age':5,'Name':'sun'}
print("rep_test:"+str(rep_test))

# 键必须不可变  用数字和字符串充当键 不能用list充当
# list_dict={['Name']:'sun','Age':13}

#Tuple是可以的 （可变的）
list_dict={('Nam'):'sun','Age':13}

　　

函数：

# coding: utf-8

# 没有参数和返回的函数
def say_hi():
     print ("sunliyuan")
 say_hi()
 say_hi()


#  有参数  无返回值
 def print_sum(a,b):
     c=a+b
     print (c)
 print_sum(1,2)

 def hellow(str):
     print("hellow" + str + "!")






# 有参数有返回值的
def repatstr(str,times):
     repeated_strs=str*times
     return repeated_strs
     
     repatstr_string=repatstr("sunliyuan",4)
 print(repatstr_string)


# 全局变量和局部变量
x = 60
def foo(x):
    print("x is :"+str(x))
    x=3
    print("change local x to"+str(x))

foo(x)
     print ('x is still',str(x))

　　

# 默认参数
def repeat_str(s, times = 1):
    repeated_strs = s * times
    return repeated_strs


repeated_strings = repeat_str("Happy Birthday!")
print(repeated_strings)


repeated_strings_2 = repeat_str("Happy Birthday!" , 4)
print(repeated_strings_2)


#不能在有默认参数后面跟随没有默认参数
#f(a, b =2)合法
#f(a = 2, b)非法

# 关键字参数: 调用函数时，选择性的传入部分参数
def func(a, b=4, c=8):
    print('a is', a, 'and b is', b, 'and c is', c)


func(13, 17)
func(125, c=24)
func(c=40, a=80)

　　

# VarArgs参数
def print_paras(fpara, *nums, **words):
    print("fpara: " + str(fpara))
    print("nums: " + str(nums))
    print("words: " + str(words))


print_paras("hello", 1, 3, 5, 7, word="python", anohter_word="java")