python - 如何将 float 四舍五入到小数点后第一位？

Question

对于一门类(class)，我要编写一个程序，将华氏温度转换为摄氏度，反之亦然。结果应四舍五入至小数点后第一位。我已经通过多种方式尝试了“round”功能，但没有成功。

temp=float(input("Enter a temperature value to convert: "))
unit=str(input("Convert to Fahrenheit or Celsius? Enter f or c: "))

if unit=="c" or unit == "C":
    degC=(temp)
    temp= (1.8*temp)+32
    print(str(temp) + " degrees fahrenheit = " + str(degC) + " degrees Celsius. ")
if unit=="f" or unit == "F":
    degF=(temp)
    temp= (temp-32)/1.8
    print(str(temp)+ " degrees celsius = " + str(degF) + " degrees Fahrenheit. ")
else:
    print("you did not enter an f or c. Goodbye ")

Answer 1

您可以使用round(number, 1)内置函数!

例如:

>>> round(45.32345, 1)

45.3

就您而言:

temp=float(input("Enter a temperature value to convert: "))
unit=str(input("Convert to Fahrenheit or Celsius? Enter f or c: "))

if unit=="c" or unit == "C":
    degC=(temp)
    temp= (1.8*temp)+32
    print(str(round(temp), 1) + " degrees fahrenheit = " + str(degC) + " degrees Celsius. ")
el*emphasized text*if unit=="f" or unit == "F":
    degF=(temp)
    temp= (temp-32)/1.8
    print(str(round(temp), 1)+ " degrees celsius = " + str(degF) + " degrees Fahrenheit. ")
else:
    print("you did not enter an f or c. Goodbye ")

Python 实际上做的是这样的:

def truncate(n, decimals=0):
    multiplier = 10 ** decimals
    return int(n * multiplier) / multiplier

您可以阅读有关 python-rounding 的更多信息

希望这有帮助!