Python检查inpu的简单程序

Question

我正在努力编写代码-有人能帮我吗？当我在Python中运行它并输入整数以外的内容时，为什么它不打印“Invalid input”？你知道吗

基本上，程序应该在无休止的循环中运行，直到我们输入“done”。所以即使在except之后，它仍然应该提示输入一个数字。你知道吗

largest = None
smallest = None
while True:
    num = raw_input("Enter a number: ")
    try:
       if num == "done" :
            print "Maximum is", largest
            print "Minimum is", smallest
            exit
       if largest is None:
           largest = num
       elif largest < num:
           largest = num
       if smallest is None:
           smallest = num
       elif smallest > num:
           smallest = num 
    except int(num) == -1:
        print "Invalid input"
        continue

Answer 1

largest = None
smallest = None
try:
    num = raw_input("Enter a number: ")
    x = int(num, base = 10)  
except:
    print "Invalid input"

while num != "done":    
    try:
    num = raw_input("Enter a number: ")
    x = int(num, base = 10)  
    except:
        print "Invalid input"
        continue

    if largest is None:
        largest = num
    elif largest < num:
        largest = num
    if smallest is None:
        smallest = num
    elif smallest > num:
        smallest = num  
print "Maximum is", largest
print "Minimum is", smallest
exit