在Python中使用条件句Try和Except

Question

我是一名初学者，在Python练习中编写了以下程序：

try:
    hours = raw_input ('Enter number of hours \n')
    int(hours)
    rate = raw_input ('Enter your hourly rate \n')
    int(rate)
except:
    print 'Enter an integer value'
    quit()
if hours > 40:
    overtime = hours - 40
    base = 40*rate
    additional = overtime * (1.5 * rate) 
    print 'Your total wage including overtime is', additional + base
else:
    wage = rate * hours
    print 'Your total wage before tax is', wage

---

但是，我收到一个TypeError in line 10 that reads unsupported operand type(s) for -: 'str' and 'int'

奇怪的是，当我输入小时数（比如10小时）和速率（比如5小时）时，它应该跳过第一个if语句，直接跳转到else语句……但由于某种原因，这并没有发生。另外，当我制作同一程序的第一个版本时，没有try和except位：

hours = float(raw_input('Enter number of hours \n'))
rate = float(raw_input('Enter your hourly rate \n'))
if hours > 40:
    overtime = hours - 40
    base = 40*rate
    additional = overtime * (1.5 * rate) 
    print 'Your total wage including overtime is', additional + base
else:
    wage = rate * hours
    print 'Your total wage before tax is', wage

---

这个很好用。你知道吗

Answer 1

从字符串到整数的转换不会保存到小时。为此，请执行以下操作：

hours=int(hours) # this is in the 3rd line of your code. Do the same for rate

Answer 2

int(hours)不到位。从docs

Return an integer object constructed from a number or string x, or return 0 if no arguments are given

您需要将其重新分配回变量

hours = int(hours)