python递归函数求回文数

python递归函数求回文数

回文数就是指整数倒过来和原整数相等。

Example 1:

Input: 121

Output: true

Example 2:

Input: -121

Output: false

Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.

Example 3:

Input: 10

Output: false

Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

1：整数转字符串，通过下标对比确定该整数是否为回文数

str_x = str(x)

for i in range(0,int(len(str_x)/2)):

if str_x[i] != str_x[-i-1]:

return False

return True

2：字符串切片操作，str[index:index:step]，中括号里面分别为：字符起点、终点和步长

str_x = str(x)

return str_x == str_x[::-1]

3：数学计算的方法，对比反转整数的值

if x<0:

return False

temp_x = x;

palindromeNum = 0

while temp_x != 0:

palindromeNum = palindromeNum*10 + temp_x%10

temp_x /= 10

return palindromeNum == x

4：整数转字符串，反转字符串，对比反转后字符串与原字符串是否相等

str_x = str(x)

str_y = ""

for i in str_x:

str_y = i + str_y

return str_y == str_x

以上这篇使用python实现回文数的四种方法小结就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。