根据 python 中的变量限制小数

Question

我正在尝试编写一个程序，使 returns golden ratio 达到小数位的限制。我到目前为止是这样的：

def gr(n):
    a, b = 0, 1
    for x in range(0, n):
        a, b = b, a+b
    else:
        return(a)

    decimals = int(input("What amount of decimals do you want to see of the golden ratio?"))
    ratio = gr(41)/gr(40)
    print(format(ratio, '2f'))

问题是我找不到将 ratio 格式化为 decimals 中的数字的方法。

Answer 1

将 precision/decimals 变量传递给 str.format:

decimals = int(input("What amount of decimals do you want to see of the golden ratio?"))
ratio = gr(41)/gr(40)
print("{:.{}f}".format(ratio,decimals))

示例：

In [3]: decimals = int(input("What amount of decimals do you want to see of the golden ratio?"))
What amount of decimals do you want to see of the golden ratio?5

In [4]: ratio = gr(41)/gr(40)

In [5]: print("{:.{}f}".format(ratio,decimals))
1.61803

Answer 2

这是您尝试执行的替代方法：

print(round(ratio, 2))

上面的代码片段会将值 ratio 舍入到小数点后两位。所以要为小数整数做这件事，你可以这样做：

print(round(ratio, decimals))

根据 python 中的变量限制小数

Limiting decimals according to variable in python

python

decimal