python3-round函数使用

#round  
#四舍五入到最近的整数
print(round(100.234))     #100
print(round(100.234,0))   #100.0

#保留指定位数小数
print(round(100.234,2))   #100.23
print(round(100.234,3))   #100.234

#对整数位数进行四舍五入
print(round(100.234,-1))  #100.0
print(round(100.234,-4))  #0.0

print(round(10011.234,-2)) #10000.0
print(round(100123.234,-3)) #100000.0
print(round(146123.234,-3)) #146000.0

#到两端的距离一样，则往偶数端取值
print(round(0.5))   #0
print(round(-0.5))  #0

#转换成二进制1，0 后可能无限位数，截断后可能比2.35小一点点，四舍五入后就是2.35
print(round(2.355,2)) #2.35
print(round(2.755,2)) #2.75