eval() 函数

eval函数就是实现list、dict、tuple与str之间的转化
str函数把list，dict，tuple转为为字符串

# 字符串转换成列表

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

结果>>
<class 'str'>
[[1, 2], [3, 4], [5, 6], [7, 8], [9, 0]]
<class 'list'>

# 字符串转换成字典

a = "{1: 'a', 2: 'b'}"
print(type(a))
b = eval(a)
print(b)
print(type(b))


结果>>
<class 'str'>
{1: 'a', 2: 'b'}
<class 'dict'>

# 字符串转换成元组

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

结果>>
<class 'str'>
([1, 2], [3, 4], [5, 6], [7, 8], (9, 0))
<class 'tuple'>