python常见数据类型转换（字符串-整数-浮点数）

• int(str) 函数将符合整数规范的字符串转换成 int 型

num = "123"
print(type(num))
num1 = int(num)
print("num1: %d" % num1)
print(type(num1))

'''
结果
<class 'str'>
num1: 123
<class 'int'>
'''

• float(str) 函数将符合浮点型规范的字符串转换成 float 型

num = "123.456"
print(type(num))
num1 = float(num)
print("num1: %d" % num1)
print(type(num1))

'''
结果
<class 'str'>
num1: 123.456000
<class 'float'>
'''

• str(num) 将整数或者浮点型转换成字符串

num1 = 123
num2 = 123.456
print(type(num1))
print(type(num2))

str1 = str(num1)
print("str1: %s" % str1)
print(type(str1))

str2 = str(num2)
print("str2: %s" % str2)
print(type(str2))

'''
结果
<class 'int'>
<class 'float'>
str1: 123
<class 'str'>
str2: 123.456
<class 'str'>
'''