Python数据类型转换

# 将 float 浮点型转化成 int 长整型
num_float = 3.5
print(num_float)
# 3.5
print(type(num_float))
# <class 'float'>
num_int = int(num_float)
print(num_int)
# 3
print(type(num_int))
# <class 'int'>

# 将 2,3 转化为复数
num_complex = complex(2,3)
print(num_complex)
# (2+3j)
print(type(num_complex))
# <class 'complex'>

# 将数字、列表、元组、字典转化为字符串类型

num_int = 45
num_str = str(num_int)
print(num_str)
# 45
print(type(num_str))
# <class 'str'>

# 将列表转化为字符串类型
num_list = [1,2,'a',5.6]
num_str = str(num_list)
print(num_str)
# [1, 2, 'a', 5.6]
print(type(num_str))
# <class 'str'>

# 将元组转化为字符串类型
num_tuple = (1,2,3)
num_str = str(num_tuple)
print(num_str)
# (1, 2, 3)
print(type(num_str))
# <class 'str'>

# 将字典转化为字符串类型
num_dict = {'a':123,'b':456}
num_str = str(num_dict)
print(num_str)
# {'a': 123, 'b': 456}
print(type(num_str))
# <class 'str'>

# repr 函数将对象转化为表达式字符串
num_str = repr(num_dict)
print(num_str)
# {'a': 123, 'b': 456}
print(type(num_str))
# <class 'str'>

# 将字符串转化为数字类型
str_num = '789'
num = eval(str_num)
print(num)
# 789
print(type(num))
# <class 'int'>

# 将列表转化成元组
lst = [1,2,3,'a']
lst_tuple = tuple(lst)
print(lst_tuple)
# (1, 2, 3, 'a')
print(type(lst_tuple))
# <class 'tuple'>

# 将元组转化成列表
tup = ('a',1,2,'m',(4,5))
tup_list = list(tup)
print(tup_list)
# ['a', 1, 2, 'm', (4, 5)]
print(type(tup_list))
# <class 'list'>

# 将列表转化成集合，用来消除多余重复元素
lst = [1,2,'a',5,'a','b']
lst_set = set(lst)
print(lst_set)
# {1, 2, 5, 'b', 'a'}
print(type(lst_tuple))
# <class 'tuple'>

#将字符串转化为集合元素
strs = "Hello world"
strs_set = set(strs)
print(strs_set)#集合中的元素是无序的
# {' ', 'w', 'e', 'd', 'r', 'o', 'H', 'l'}
print(type(strs_set))
# <class 'set'>

# 将整数转化为字符。
print(chr(65))
# A
print(chr(90))
# Z
print(chr(97))
# a
print(chr(122))
# z

# 将字符转化为整数。
print(ord('A'))
# 65
# 将十进制整数转化为十六进制数。
print(hex(17))
# 0x11
# 将十进制整数转化为八进制数。
print(oct(9))
# 0o11