Python 将变量值打印到小数点后两位
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printing a variable value to 2 decimal places
提问by user2633836
I am trying to create a currency converter that prints a final value out to 2 decimal places.
我正在尝试创建一个货币转换器，将最终值打印到小数点后两位。
I have created the entire program and this is just a small portion of it but I can't get the program to print to 2 decimal places. I have tried using "%.2f" from previously asked questions but it doesn't work can anybody suggest what I need to do?
我已经创建了整个程序，这只是其中的一小部分，但我无法将程序打印到小数点后两位。我曾尝试使用先前提出的问题中的“%.2f”，但它不起作用有人可以建议我需要做什么吗？
The program I have so far is
我到目前为止的程序是
conversion_Menu= "What do you want to convert?\n1.Pound Sterling\n2.Euro\n3.USD\n4.Japanese Yen"
x = input (conversion_Menu)
if x == "1":
sterling_Menu = "What do you want to convert to?\n1.Euro's\n2.USD\n3.Japanese Yen"
y = input (sterling_Menu)
currency_Total = float(input("How much do you wish to exchange?"))
total_Exchange = currency_Total * sterling_Conversion
print ("This converts to", total_Exchange)
I want to guarantee that the value stored in variable total-Exchange is always to 2 dp.
我想保证存储在变量 total-Exchange 中的值始终为 2 dp。
回答by Dux
If you want the value to be stored with 2 digits precision, use round():
如果您希望以 2 位精度存储值，请使用round()：
>>>t = 12.987876
>>>round(t,2)
#12.99
If you need the variable to be saved with more precision (e.g. for further calculations), but the output to be rounded, the suggested "%.2f"works perfectly for me:
如果您需要更精确地保存变量（例如用于进一步计算），但输出要四舍五入，则建议"%.2f"对我来说非常适合：
>>>t = 12.987876
>>>print "This converts to %.2f" % t
#This converts to 12.99
回答by KevinB
Tested with Python 3.0
用 Python 3.0 测试
t = 12.987876
print(f'This converts to {t:.2f}')
Result:
结果：
This converts to 12.99
这将转换为 12.99
