Convert between Python data types (dictionaries, strings, lists, tuples)

The eval function is to realize the conversion between list, dict, tuple and str

The str function converts list, dict, and tuple to strings

#-*-coding:utf-8-*-

#1、字典

dict  =  { 'name' : 'Zara' , 'age' : 7 , 'class' : 'First' }

#字典转为字符串，返回：<type 'str'> {'age': 7, 'name': 'Zara', 'class': 'First'}

print  type ( str ( dict )), str ( dict )

#字典可以转为元组，返回：('age', 'name', 'class')

print  tuple ( dict )

#字典可以转为元组，返回：(7, 'Zara', 'First')

print  tuple ( dict .values())

#字典转为列表，返回：['age', 'name', 'class']

print  list ( dict )

#字典转为列表

print  dict .values




#2、元组

tup = ( 1 , 2 , 3 , 4 , 5 )

#元组转为字符串，返回：(1, 2, 3, 4, 5)

print  tup.__str__()

#元组转为列表，返回：[1, 2, 3, 4, 5]

print  list (tup)

#元组不可以转为字典

#3、列表

nums = [ 1 , 3 , 5 , 7 , 8 , 13 , 20 ];

#列表转为字符串，返回：[1, 3, 5, 7, 8, 13, 20]

print  str (nums)

#列表转为元组，返回：(1, 3, 5, 7, 8, 13, 20)

print  tuple (nums)

#列表不可以转为字典

#4、字符串

#字符串转为元组，返回：(1, 2, 3)

print  tuple ( eval ( "(1,2,3)" ))

#字符串转为列表，返回：[1, 2, 3]

print  list ( eval ( "(1,2,3)" ))

#字符串转为字典，返回：<type 'dict'>

print  type ( eval ( "{'name':'ljq', 'age':24}" ))

# Convert string to list 
a = "[[1,2], [3,4], [5,6], [7,8], [9,0]]" 
print(type(a)) 
b = eval(a) 
print(b)

# Convert string to dictionary 
a = "{1: 'a', 2: 'b'}" 
print(type(a)) 
b = eval(a) 
print(type(b)) 
print(b)

# Convert string to tuple 
a = "([1,2], [3,4], [5,6], [7,8], (9,0))" 
print(type(a)) 
b =eval(a) 
print(type(b)) 
print(b)