python数字类型

1. 数字类型的表达式

数字类型的表达式
+ - 数字相加或者相加 a + b , a - b
* / 数字相乘或者相除 a * b , a / b
%   数字取余        a % b,
//  返回商的整数部分 a // b
**  指数，平方      a ** b

示例：

num_1 = 4
num_2 = 1
print(num_1 - num_2) # 3
print(num_1 + num_2) # 5
print(num_1 * num_2) # 4
print(num_1 / num_2) # 4.0

num_1 = 9
num_2 = 2
print(num_1 % num_2) # 1
print(num_1 // num_2) # 4

num_1 = 2
num_2 = 2
print(num_1 ** num_2) # 4

2. 赋值表达式

赋值运算符
+=  加法赋值运算 a += c, a = a + c
-=  减法赋值运算 a -= c, a = a - c
*=  乘法赋值运算 a *= c, a = a * c
/=  除法赋值运算 a -= c, a = a / c
%=  取余赋值运算 a -= c, a = a % c
//= 取商赋值运算 a -= c, a = a // c
**= 幂赋值运算   a -= c, a = a ** c

示例：

num_1 = 2
num_2 = 2
num_1 **= num_2
print(num_1) # 4
num_1 %= num_2
print(num_1) # 0
num_1 //= num_2
print(num_1) # 0

3. 不同数据类型的相互转换

# 类型转换
name = "王拿铁"
age = 18
time = 13.25

age_str = str(age)
time_str = str(time)
age_int = int(age)
time_int = int(time)
age_flo = float(age)
time_flo = float(time)
print(age_str) # 18
print(time_str) # 13.25
print(age_int) # 18
print(time_int) # 13 不遵循四舍五入 直接舍去小数点后边
print(age_flo) # 18.0
print(time_flo) # 13.25

4. str类型转int必须保证字符串中全部是数字。

name = "王拿铁"
age = "18"
# name_int = int(name) # ValueError: invalid literal for int() with base 10: '王拿铁'
# print(name_int)
age_int = int(age)
print(age_int) # 18

5. 数据类型检测，type()

name = "王拿铁"
age = 18
time = 13.25
print(type(name))
print(type(age))

6. input输入语句

print("请告诉我你是谁")
name = input()
print(f"哦~！，原来你是{name}")

精简写法：

name = input("请告诉我你是谁") # *input只返回字符串类型
print(f"哦~！，原来你是{name}")