我在这里没有看到我的错误 - 尝试学习 Python

Question

I'm trying to become comfortable with python. I've been trying some simple activities that I've given in my beginning c++ classes when I was teaching. I did one involving functions and writing a file which worked flawlessly. I thought this one would be easier. It acts like it is in a silent endless loop, but it won't even let me trace it. Can someone see where I am going awry?

# Find Adam Numbers

def isAdamNumber(candidate):
    isAdam = False
    rev = reverse(candidate)
    square = candidate * candidate
    revsq = rev*rev
    if revsq == reverse(square):
        isAdam = True
    return isAdam
    
def reverse(num):
    rev=0
    while num > 0:
        rev = rev * 10 + num%10
        num/=10
    return rev
for x in range (11,25):
    if isAdamNumber(x):
        print(x, " is an adam number\n")

Answer 1

快速修复是将/=更改为整数除法版本， //=

Answer 2

Inside the reverse function, you are going into an infinite loop. num value always will be greater than 0, therefore the while loop will continuously run. In python, you can get the reverse of the function without much effort. Convert the integer to string and reverse the string and now change the string back to integer.

def reverse(num):
    num_str = str(num)[::-1]
    return int(num_str)

I think this function definition can solve your problem. To visualize the python to learn and teach, use this link

Answer 3

num > 0 is never False . Dividing a positive number by 10 repeatedly makes it smaller, but it never becomes zero, so the while loop keeps repeating.

Use //= instead. It rounds to the nearest integer, so it will reach 0.

This also wouldn't reverse numbers (unless I'm missing something). Alternatively, you can use

int(str(num)[::-1])

which converts the number to a string, reverses it using slicing , and turns it back into an integer.

Answer 4

The problem has already been addressed by the other answers, so here's the expanded and simplified version of the slicing that's going on [this doesn't actually use slicing]:

def reverse(num):
    rev = ''
    num = str(num)
    for i in range(len(num) - 1, -1, -1):
        rev += num[i]
    return int(rev)

This counts backward from the last element in the string version of num , and adds all the elements of num (in reverse order) to rev.