Question

import easygui as eg 
import sys

version = 'Percentage Calculator'

Options = [ 'Percantage Increase', 'Percentage Decrease' ]

button = eg.buttonbox ('What would you like to calculate', title = version, choices =     Options)

if button == Options [0]:
    enter = eg.enterbox ('Please enter a number between 0 and 999.', title = version,     strip=False)
    if enter < '0' or enter > '999':
            eg.msgbox ('please choose a number between 0 and 999.', title = version,     ok_button='OK')
            sys.exit()
    enter2 = eg.enterbox ('please enter a number between 0 and 999, that is bigger than     the first number.', title = version, strip=False)
    if enter2 < '0' or enter2 > '999':
            eg.msgbox ('please choose a number between 0 and 999.', title = version,     ok_button='OK')
            sys.exit()
    elif enter2 < var enter:
            eg.msgbox ('please choose a number bigger than the first number.', title =     version, ok_button='OK')
            sys.exit()
    Subtract = enter2 - enter
    print (Subtract)

这是我的代码...正如你所看到的，在底部附近，它表示'enter2 - enter'我希望这减去用户从第一个数字输入的第二个数字，但它只是说......

Traceback (most recent call last):
  File "C:\Users\olitr_000\Desktop\PYTHON\Percentage Calculator\Percentage     Calculator.py", line 22, in <module>
    Subtract = enter2 - enter
TypeError: unsupported operand type(s) for -: 'str' and 'str'

我该怎么做才能说输入1等于55而输入2 = 198我怎么能得到它以便它确实198-55？

请帮忙，如果您需要更多信息，请通知我。

Answer 1

你不能减去两个字符串，把第一个字符串转换成整数。

Subtract = int(enter2) - int(enter)

Answer 2

你的问题是，通过使用eg.enterbox函数，用户输入的数字将被视为字符串。为了解决这个问题，我们将enterbox返回的'string'发送到int（）函数。这会将数字字符串转换为可用于减去其他整数的实际整数。

例如

enter = "3"
enter = int(enter)
enter2 = "4" #This is an example of what the variable looks like coming from the enterbox
enter2 = int(enter2) #enter2 now looks like 4 instead of "4"

output = enter2 - enter #this will return 1 to the variable output

希望这会有所帮助;）

哦，你不需要这一行中的引号：

if enter < '0' or enter > '999':

正如你所说'0'是一个字符串，不应被视为数字;）

Answer 3

这会对你有帮助。

import easygui as eg 
import sys

version = 'Percentage Calculator'

Options = [ 'Percantage Increase', 'Percentage Decrease' ]

button = eg.buttonbox ('What would you like to calculate', title = version, choices =     Options)

if button == Options [0]:
    enter = eg.enterbox ('Please enter a number between 0 and 999.', title = version,     strip=False)
    if enter < '0' or enter > '999':
            eg.msgbox ('please choose a number between 0 and 999.', title = version,     ok_button='OK')
            sys.exit()
    enter2 = eg.enterbox ('please enter a number between 0 and 999, that is bigger than     the first number.', title = version, strip=False)
    if enter2 < '0' or enter2 > '999':
            eg.msgbox ('please choose a number between 0 and 999.', title = version,     ok_button='OK')
            sys.exit()
    elif enter2 < var enter:
            eg.msgbox ('please choose a number bigger than the first number.', title =     version, ok_button='OK')
            sys.exit()
    Subtract = int(enter2) - int(enter)
    print (Subtract)

Answer 4

我认为你在这里遇到的问题只是parsing，因为我们知道Python不接受键盘中的string值，因为代码中没有变量类型定义，即为什么我们总是需要将输入转换或解析为适当的类型。

>>> a = "3.14"
>>> float(a)
3.14
>>> int(float(a))
3

如何从python中的另一个变量中减去一个变量

4 个答案: