Palindrome Program in Python using for loop [New]

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Palindrome program in python using for loop

number=input("Enter any number/word :")
i=0
for i in range(len(number)):
    if number[i]!=number[-1-i]:
        print('It is not a palindrome')
        break
else:
    print('It is a palindrome')

Output:

Enter any number:5665 It is a palindrome

Palindrome String Program in Python using while loop

In this program, we will take two pointers i and j. Variable "i" will point to the leftmost characters of the string and "j" will point to the rightmost character. If they are the same then will increase "i" by 1 and decrease j by 1 and so on. If at any index, the characters present at these indexes are different then the given string is not a palindrome.

str=input("Enter String: ")
i=0
j=len(str)-1
isPalindrome=True
while i<=j:
    if(str[i]!=str[j]):
        isPalindrome=False
        break
    i+=1
    j-=1

if isPalindrome:
    print(f"{str} is Palindrome.")
else:
    print(f"{str} is not a Palindrome.")

Output:

Enter String: racecar racecar is Palindrome.

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Video Solution

Using an inbuilt reversed function

word=input("Enter any word :")
rev=reversed(word)
if list(word)==list(rev):
    print('It is a palindrome')
else:
    print('It is not a palindrome')

Output:

Enter any word: madam It is a palindrome

Approach to check whether the given string is palindrome or not using an inbuilt reversed function:

First, we input the string using the input() function.
Using the reversed() function, we reverse the word entered by the user and assign it to a new variable called rev.
Using the if statement, we compare the list(word) & list(rev). If they are the same, then we will print "it is a palindrome", and if they are not the same, we will print "it is not a palindrome".

Valid Palindrome leetcode accepted solution in python

First, we have to remove all non-alphanumeric characters in the given string, and then convert all upper-case letters into lower-case letters. Then we have to check whether the converted string is a valid palindrome or not. A valid palindrome is one which read the same forward and backwards.
Problem Link

import re
class Solution:
    def isPalindrome(self, s: str) -> bool:
        str1="".join(re.split("[^a-zA-Z0-9]*",s)).lower()
        i=0
        j=len(str1)-1
        isPalindrome=True
        while i<=j:
            if str1[i]!=str1[j]:
                isPalindrome=False
                break
            i+=1
            j-=1
        return isPalindrome

Q. What is a palindrome number in python?

A number is a palindrome when its reverse is also the same as the original number.

To check whether a number is a palindrome or not, we have to reverse the number using the reversed() function. Then we compare the actual and reversed numbers using the if statement.

for example:8558, is a palindrome

Q. How do you write a palindrome program in python using for loop?

First, we input a number using the input() function, then reverse it using the reversed() function. Then we compare the number (or a word) with its reverse if the actual number and the reversed number are the same, and then we print the number entered as a palindrome. Else, we print the number entered is not a palindrome.

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Palindrome Program in Python using for loop [New]