Как проверить слово на палиндром python

Проверьте, является ли строка палиндромом в Python

В этом руководстве обсуждаются методы проверки того, является ли строка палиндромом в Python.

Проверьте, является ли строка палиндромом, используя метод нарезки списка в Python

Строка палиндрома — это слово, которое читается одинаково вперед и назад. Например, слово madam останется прежним, если в нем перевернуть последовательность букв; этот тип слова называется палиндромом.

Мы можем проверить строки палиндрома, перевернув исходную строку и сравнив каждый элемент исходной строки с каждым элементом перевернутой строки; это можно сделать с помощью нарезки списка. Следующая программа ниже показывает нам, как проверить, является ли строка палиндромом или нет, с помощью метода нарезки списка.

Мы проверили, является ли строка ma#am палиндромом, с помощью метода нарезки списка в приведенном выше коде. Сначала мы вычислили обратное значение исходного слова с [::-1] в качестве индекса списка. Затем мы сравнили каждый индекс с оператором равенства == . Если совпадают и исходное, и обратное слово, печатаем на консоли Palindrome ; в противном случае печатаем Not Palindrome .

Проверьте, является ли строка палиндромом, используя функцию reversed() в Python

Функция reversed() принимает последовательность элементов и возвращает обратный итератор для этой последовательности. Поскольку строка представляет собой последовательность символов, мы также можем использовать функцию reversed() вместо индекса списка [::-1] , чтобы перевернуть последовательность символов внутри строки. Затем мы можем поэлементно сравнить как исходную, так и перевернутую строку, чтобы определить, является ли это палиндромом или нет. Следующий фрагмент программы демонстрирует, как проверить, является ли строка палиндромом или нет, с помощью функции reversed() .

Python Palindrome Program With Examples

Do you know what is palindrome? In this Python tutorial, we will understand how to write a Python Program to check if it is a palindrome or not. Also, we are going to cover the below topics.

• Write a Python Palindrome program string
• Write a Python Palindrome program number
• Write a Python Palindrome program using loop
• Write a Python Palindrome program using recursion
• How to write a longest Palindrome Python program
• Python program for palindrome or not
• Write a Python program to check if it is palindrome or not
• How to write a palindrome program in python without using the string function
• Write a palindrome program in python using the reverse function
• Write a Python Program to print palindrome numbers between 1 to 100
• Python Program to find palindrome word
• Write a palindrome program in python using a while loop
• Write a palindrome program in python using if else
• Write a palindrome program in python using slicing
• Write a palindrome program in python using a list

Table of Contents

Python palindrome program

• Any number or string that remains unchanged when reversed is known as a palindrome.
• A palindrome is a word or a set of numbers made up of letters that spell the same word when reading both forward and backward. Python Palindrome permits punctuation, symbols, letters, and spaces within the Palindrome words.
• It works by comparing the actual word and the reverse of the word, and if there is an exact match, the matched value is True. Python has three different forms of palindrome methodology: number palindrome, multiple-word palindrome, and single-word palindrome.
• For example, “mom” is the same in forwarding or reverse direction.

Example:

To check for palindromes, the above program first takes input from the user (using the input function). Next, determine whether the string has been reversed using the slice operation [start:end: step]. The step value of -1 in this case reverses the string and it will check the condition of whether the string is palindrome or not.

Here is the implementation of the following given code.

This is how we can create a Palindrome program in Python.

Python Palindrome program string

• Here we will discuss how to use the string input in the case of a palindrome program.
• Every character in a String was iterated in this Python application using a For Loop. Each character is given an str1 value inside the for loop (before). The palindrome string was then checked using a Python if statement.

Example:

Here is the Screenshot of the following given code

As you can see in the Screenshot we have used the string input value in Palindrome Program.

Python Palindrome program number

• When reversed, a number must remain the same to qualify as a palindrome. It is not a palindrome if the number does not equal the reverse of itself.
• The integer will be converted to a string format and then the string will be reversed using this approach. The final step will involve verifying that the changed number corresponds to the original.
• To convert the integer number to a string we can easily use the str() function. By using string slicing, it will reverse the number.

Example:

In the given example we have used the input statement and then used the str() function to convert the integer value to a string. It will check the condition if the number is reversed then it will return it as a palindrome otherwise it will return “it is not a palindrome’.

Here is the implementation of the following given code.

This is how to create a Palindrome Program by using integer numbers in Python.

Python Palindrome program using loop

• Let us create a palindrome program by using for loop in Python.
• If the reverse number is equal to the same number then the element is called a palindrome number. For example 121=121 So, 121 is a palindrome number.
• we will mention integer numbers while declaring the variables. Then it will check the condition if the number is equal to the reverse number by using the if-else statement.

Example:

You can refer to the below Screenshot

In this example, we have understood how to create a palindrome program by using for loop in Python.

Python Palindrome program using recursion

• Simple indexing and a user-defined function are used in conjunction with recursion when it is necessary to determine whether or not a text is a palindrome.
• Palindromes are strings or values that have the same characters in each of their respective indexes when read from right to left and left to right.
• The recursion computes the results of the smaller components of the larger problem and then combines these components to get the larger problem’s solution.

Example:

In the following given code first, we define the function ‘check_palindrome’ and within this parenthesis, we passed the ‘n’ keyword as an argument. Next, we set the condition if the length of the number is greater than 1 then it will satisfy the condition (n[1:-1]).

Here is the execution of the following given code.

This is how to create a palindrome program by using the recursion method.

longest Palindrome Python program

• Let’s say we have the string S. The longest palindromic substring in S must be located. We are assuming that the string S is 1000 characters long. Therefore, “C” is the longest palindromic substring if the string is “California”.

Let’s take an example and check how to find the longest palindrome string in Python.

Source Code:

Here is the implementation of the following given code

Python program for palindrome or not

• A palindrome is a word or a set of numbers made up of letters that spell the same word when reading both forward and backward. Python Palindrome permits punctuation, symbols, letters, and even spaces within the Palindrome words.
• It works by comparing the actual word and the reverse of the word, and if there is an exact match, the matched value is True. Python has three different forms of palindrome methodology: number palindrome, multiple-word palindrome, and single-word palindrome.
• First, we will read the number, and then In a temporary variable, store the letter or number. Next, reverse the number and Compare the temporary variable to a letter or integer that has been reversed.
• Print “This string/number is a palindrome” if the two characters or digits are the same. “This string/number is not a palindrome,” if not, print.

Example:

In the following given code first, we will declare the variable and assign the integer number to it. Next, we will use the str() function and which will convert the integer number into the string and assign the reversed number.

Next, we set the condition that the given number is equal to the reverse number or not. If it is equal then it is a palindrome otherwise it will display it is not a palindrome number.

You can refer to the below Screenshot

This is how we can check whether the program is palindrome or not in Python.

Python program to check if it is palindrome or not

• Here we will discuss whether the string or number is palindrome or not in Python.
• A group of digits called a palindrome number stays the same when read backward. Additionally, it is reversed that these numbers are symmetrical. Its digits are equal to the original number when they are inverted. For instance, the number 121 is a palindrome.
• The first step is to number in reverse order and the second step we will compare with the number before the operation.

Example:

Let’s take an example and check whether the string is palindrome or not in Python.

Source Code:

In the following given code first, we define the function ‘Palindrome’ function and within this parenthesis, we assigned the variable ‘t’ and set the reverse condition t[::-1]. Next, we will set the condition of the result as palindrome or not.

You can refer to the below Screenshot.

palindrome program in python without using the string function

• To check the palindrome number in Python, we may also use a function. and the string is referred to as a palindrome if its reverse contains the same string.
• In this example, we are not going to use the string function instead of that we will declare a variable and assign the string in which we want to check whether the string is palindrome or not.
• Next, we will create another variable in which the reversed string will be stored and then we used the for-loop method and set the condition if the original number == reversed number. If it is equal then it is a palindrome otherwise it will return it is not a palindrome.

Example:

Here is the execution of the following given code

In this example, we have understood how to check the palindrome number in Python without using the string function.

Palindrome program in python using reverse function

• In this example, we will discuss how to create a palindrome program in Python by using the reverse function.
• To perform this task we are going to use the reversed function and Python has a built-in method called reversed that may be used to acquire a sequence’s iterator in reverse.
• The reversed function is similar to the iter() method but with the reversed order. An object used to iterate over an iterable is called an iterator. The iter method on an iterable allows us to create an iterator object.

Example:

Here is the implementation of the following given code

This is how to create a Palindrome Program in Python by using the reverse function.

Python Program to print palindrome numbers between 1 to 100

• Let us discuss how to print the palindrome numbers between 1 to 100 in Python.
• When a number is reversed and the result is the same as the original, it is said to be a palindrome.
• The user can input the upper limit value using this Python program. The program then produces palindrome numbers from 1 to the user-entered integer. To start, we iterated a loop between 1 and the maximum value using the For Loop.

Example:

In the following given code first, we used the input function and enter the integer values. Next, we iterate the values from 1 to 100.

Here is the implementation of the following given code.

This is how we can print the palindrome numbers between 1 to 100 in Python.

Python Program to find palindrome word

• When reversed, a number must remain the same to qualify as a palindrome. It is not a palindrome if the number does not equal the reverse of itself.
• The integer will be converted to a string format and then the string will be reversed using this approach. The final step will involve verifying that the changed number corresponds to the original.

Example:

You can refer to the below Screenshot

In this example, we have understood how to display the palindrome word.

palindrome program in python using a while loop

• In this section, we will discuss how we can use the while loop concept to display the palindrome number.
• A code block’s iteration of the while loop in Python runs each time the provided condition, or conditional expression, is true.

Example:

First, we will take an input number from the user and then utilize a while loop to reverse a specified integer. The original and reverse numbers should be compared. The number is a Python palindrome if both numbers exactly matched.

You can refer to the below Screenshot.

As you can see in the Screenshot we have checked whether the number is palindrome or not by using for loop.

palindrome program in python using if else

• In this section, we will discuss how to check whether it is a palindrome or not by using the if-else condition in Python.
• The reversed string will be located for this procedure, as mentioned before, and then it will be compared to the original string.

Example:

In this example, we have used the input function and set the condition if(new_str == empty_string): it will check if the string is palindrome or not.

Here is the implementation of the following given code.

This is how we can check whether the number is palindrome or not by using the if-else condition.

Palindrome program in python using slicing

• In this example, we will discuss how to use the slicing method for returning the palindrome number.
• To check for palindromes, the above program first takes input from the user (using the input function). Next, determine whether the string has been reversed using the slice operation [start:end: step].
• The step value of -1 in this case reverses the string and it will check the condition of whether the string is palindrome or not.

Example:

Here is the Output of the following given code

palindrome program in python using a list

• In this section, we will discuss how to use the list and check whether it is a palindrome or not.
• A method called “check palindrome list” that accepts a string as a parameter is defined. The original string is compared to the inverted string.
• A list is defined outside the method and shown on the console and it is repeated, and the elements are joined together using the “join” technique before being turned into a string and the necessary parameter is passed when calling the method.

Example:

Here is the execution of the following given code

Here is the list of some more related Python tutorials.

In this article, we have discussed how to create a palindrome program in python, and also we have checked if it is a palindrome or not also we have covered the below topics.

• Write a Python Palindrome program string
• Write a Python Palindrome program number
• Write a Python Palindrome program using loop
• Write a Python Palindrome program using recursion
• How to write a longest Palindrome Python program
• Python program for palindrome or not
• Write a Python program to check if it is palindrome or not
• How to write a palindrome program in python without using the string function
• Write a palindrome program in python using the reverse function
• Write a Python Program to print palindrome numbers between 1 to 100
• Python Program to find palindrome word
• Write a palindrome program in python using a while loop
• Write a palindrome program in python using if else
• Write a palindrome program in python using slicing
• Write a palindrome program in python using a list

I am Bijay Kumar, a Microsoft MVP in SharePoint. Apart from SharePoint, I started working on Python, Machine learning, and artificial intelligence for the last 5 years. During this time I got expertise in various Python libraries also like Tkinter, Pandas, NumPy, Turtle, Django, Matplotlib, Tensorflow, Scipy, Scikit-Learn, etc… for various clients in the United States, Canada, the United Kingdom, Australia, New Zealand, etc. Check out my profile.

7 Ways to Solve Palindrome Python Programs

One of the most basic and commonly asked interview questions is to check whether a string is a palindrome or not using python. A palindrome is a string or a number that, if we reverse, equals the original value. For example- if we reverse the string MALAYALAM, we will get back the original string. Also, if we reverse the number 12321, we will get 12321 back. These are known as palindromes.

In this article, we will learn how to check whether a string or a number is a palindrome or not in many different ways. In addition to it, we will solve some fun questions which are commonly asked in competitions and interviews.

Checking Whether a String is a Palindrome in Python

Check Palindrome Using Slicing in Python Check Palindrome Using reversed() Function In Python Check Palindrome Using Using While Loop In Python Checking Whether a Number is a Palindrome in Python Using Loop Checking Whether a Phrase is a Palindrome in Python To find the Palindromic longest substring in a string

1. Check Palindrome Using Slicing in Python

We can use the concept of slicing to reverse the string, and then we can check whether the reverses string is equal to the original string or not.

The above method is straightforward to use and also a good method, and you can use it in competitions, but people generally don’t prefer to use it in interviews. This method is so simple, and people prefer to code from scratch to make this kind of program to show their skills. We will study that approach too in the following section.

2. Check Palindrome Using Loop In Python

3. Check Palindrome Using reversed() Function In Python

4. Check Palindrome Using Using While Loop In Python

5. Checking Whether a Number is a Palindrome in Python Using Loop

We are going to use the following concept-
Number=12321
The remainder of this number, when divided by 10, is:
Number%10=12321%10=1
Reverse_Number=Remainder=1
Then, we will divide the number by 10.
Number=Number/10=12321//10=1232
Remainder=1232%10=2
Reverse_Number=Remainder=12
Number= 1232/10=123
Remainder=123%10=3
Reverse_Number=Remainder=123
Number= 123/10=12
Remainder=12%10=2
Reverse_Number=Remainder=1232
Number= 12/10=1
Remainder=1%10=1
Reverse_Number=Remainder=12321

We can also first convert the number into a string and then apply any of the methods above to check if the number is palindrome or not.

6. Checking Whether a Phrase is a Palindrome in Python

Checking if a phrase is a palindrome or not is different from checking if a word is a palindrome or not. So, we cannot apply any of the above methods for a phrase.
For example- The phrase ‘Too hot to hoot’ is a palindrome if you ignore the upper case – lower case and spaces in the characters.

There are some other types of palindromes, like- ‘Is it crazy how saying sentences backward creates backward sentences saying how crazy it is.’ It is different from other palindromes we have discussed until now because here, if we reverse the characters, it is not a palindrome. But if we reverse it word by word, it is a palindrome.

7. To find the Palindromic longest substring in a string

A very common and interesting question on palindromes is to find the longest substring, which is a palindrome from a string that may or may not be a palindrome. I suggest you try it yourself once and then look at the solution below.
There are many ways to solve this problem. We will go for the easiest one which all of us will be able to understand easily.

The time complexity for the above program is O(n^2) as we have a for loop inside a for a loop.

Must Read

Conclusion

We have studied what a palindrome is, how to check whether a string or a number is a palindrome. We have also covered some common interview questions like checking for a phrase if it is a palindrome and finding the longest substring, which is a palindrome in python. I hope you will try each problem, and please comment down if you face any issues in it.

How to Check for Palindrome in Python

A palindrome is a word/phrase that reads the same backward as it does forward. The “racecar” and “madam” are examples of palindromes. Python presents various inbuilt methods that are used to check for palindromes.

This Python blog provides a detailed comprehensive tutorial on the approaches to check if the string is a palindrome.

How to Check/Verify if a Python String is Palindrome?

In Python, there are a number of methods for determining if a particular string is a palindrome. Here are the followings methods:

Method 1: Applying the “for” Loop to Check For Palindrome

The “for” loop can be employed to calculate if a string is a palindrome. To do this, iterate over a string from the beginning to the end, comparing each character with the character at the opposite end of the string. The characters of a palindrome are identical in both directions.

Example

The below code uses the “for” loop to check/verify for palindromes:

In the above code:

• The user-defined function “is_palindrome()” takes a string as a parameter/argument and retrieves “True” if the particular string is a palindrome, otherwise “False”.
• The “for” loop is used inside the function to iterate over the first half of the string and compare each character with the corresponding character from the end of the string.
• If any pair of characters do not match, the function returns “False” immediately, as this means the string is not a palindrome.
• If the loop finishes without finding any mismatch, the function returns “True”, which indicates that the string is a palindrome.
• Finally, access the function “is_palindrome()” on the two passed strings i.e., “racecar” and “python”, respectively.

Output

Based on the above output, it can be implied that the first string is a palindrome whereas the second string is not.

Method 2: Applying the “reversed()” Method to Check For Palindrome

The “reversed()” method retrieves a reversed iterator for the given iterable. This method reverses the order of a string and then checks for equality with the original string.

Example

The following code utilizes the “reversed()” method to check the palindrome condition:

In the above code snippet, the user-defined function named “is_palindrome()” utilizes the combined “reversed()” and “join()” methods to check whether the passed strings are palindrome or not one by one.

Output

The above output verifies if the passed string is palindrome or not by retrieving the corresponding boolean value.

Method 3: Applying the “String Slicing” Technique to Check For Palindrome

Slicing strings in Python involves specifying start and end indices for a string, and setting a step size if desired. This technique can be utilized to verify the palindrome in Python:

Example

The below code checks for palindrome condition:

In the above code lines:

• The “sub()” method is used inside the user-defined function to remove any non-alphanumeric characters from the string.
• The “lower()” method is used to convert the string to lowercase.
• Lastly, the “string slicing” technique is used to match the reversed string with the given/original string.
• After defining the user-defined function, at the end of the program, the function is accessed/called on the specified passed strings to check for palindrome.

Output

The above output indicates that the first string is a palindrome, whereas it is not the case in the second string.

Conclusion

To check whether the given string is palindrome or not, the “for” loop, the “reversed()” method, or the “slicing” technique is used in Python. The “for” loop iterates over the string from beginning to end and compares each character with its opposite to check for the discussed condition. Similarly, the “reversed()” method and “String Slicing” can also be used to check whether the given string is palindrome or not. This tutorial provided an in-depth guide on checking for palindrome conditions in Python.

About the author

Talha Saif Malik

Talha is a contributor at Linux Hint with a vision to bring value and do useful things for the world. He loves to read, write and speak about Linux, Data, Computers and Technology.