对不同大小的浮点值执行算术运算

Question

如果一个浮点变量有 5 个数字，其他有 4 个数字，并且对它们执行算术运算，我的代码没有运行我期望的那样。例如：

def capacity(self):

    mmax = self.mmax.get()
    current = self.current.get()
    mmin = self.mmin.get()

    flag = False

    if flag is False:
        if mmax.isdigit() and mmin.isdigit() and current.isdigit():
            capacity = float(100 * ((float(current) - float(mmin)) / (float(mmax) - float(mmin))))
            if mmin <= current <= mmax and 0 <= capacity <= 100:
                flag = True
            else:
                self.result = str("Please ensure the values entered correspond to the correct value.")
        else:
            self.result = str("Please enter only positive integers.")

    if flag is True:
        self.result = "Capacity: %2.2f" % capacity + '%'

如果mmax = 10000, current = 5000, and mmin = 1000,self.result = str("Please ensure...").
如mmax = 9999, current = 5000, and mmin = 1000,self.result = str("Capacity: 44.45%).

这是怎么回事/我该如何解决这个问题？

Answer 1

我猜 mmin 和 current 以及 mmax 是字符串。在这种情况下，这个表达式：

if mmin <= current <= mmax and 0 <= capacity <= 100:

... 正在对值进行字典顺序比较。这与数值比较不同：例如，"5000" < "10000" 计算结果为 False，因为“5”大于“1”。

在对它们进行比较之前将您的值转换为数字。

if mmax.isdigit() and mmin.isdigit() and current.isdigit():
    mmax = float(mmax)
    current = float(current)
    mmin = float(mmin)

    capacity = float(100 * ... #etc

或

if float(mmin) <= float(current) <= float(mmax) and 0 <= capacity <= 100:

对不同大小的浮点值执行算术运算

Performing arithmetic on floating point values of different sizes

python

floating-point

size

tkinter

tkinter-entry