# Python program to check whether number formed by combining all elements of the array is palindrome

• Difficulty Level : Easy
• Last Updated : 21 Nov, 2021

Given an array arr[], the task is to combine all the elements in the array sequentially and check if it is a palindrome.

Examples:

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Input: arr[] ={1 , 69 , 54 , 45 , 96 , 1}

Output: palindrome

Explanation: The number formed by combining all the elements is “1695445961” which is a palindrome

Input: arr[] ={2 , 73 , 95 , 59 , 96 , 2}

Output: not palindrome

Explanation: The number formed by combining all the elements is “2739559962” which is not a palindrome

Method 1: Using map() and join()

• Convert each element of the list to a string using map() function.
• Join the list using join() function.
• Check if it is a palindrome.
• If yes then print palindrome.
• If no print, not a palindrome.

Below is the implementation of the above approach:

## Python3

 `# function to check palindrome``def` `checkPalindrome(string):``  ` `    ``# reverse the string``    ``rev ``=` `string[::``-``1``]``    ` `    ``# checking if string is equal to reverse``    ``if``(string ``=``=` `rev):``        ``return` `True``    ``else``:``        ``return` `False` `# function to convert list to single number string``def` `joinArray(lis):``  ` `    ``# convert the elements of list to string``    ``lis ``=` `list``(``map``(``str``, lis))``    ` `    ``# converting list to string``    ``number ``=` `''.join(lis)``    ` `    ``# checking if it is palindrome``    ``if``(checkPalindrome(number)):``        ``return` `True``    ``else``:``        ``return` `False` `# Driver code``lis ``=` `[``1``, ``76``, ``39``, ``93``, ``67``, ``1``]``if``(joinArray(lis)):``    ``print``(``"Palindrome"``)``else``:``    ``print``(``"not Palindrome"``)`

Output:

`Palindrome`

Time Complexity: O(n)

Method 2: Using type casting and string concatenation

• Take an empty string say str.
• Traverse through the list and convert each element to string using type casting
• Add this to str using string concatenation
• Check if str is a palindrome

Below is the implementation of the above approach:

## Python3

 `# function to check palindrome``def` `checkPalindrome(string):``  ` `    ``# reverse the string``    ``rev ``=` `string[::``-``1``]``    ` `    ``# checking if string is equal to reverse``    ``if``(string ``=``=` `rev):``        ``return` `True``    ``else``:``        ``return` `False` `# function to convert list to single number string``def` `joinArray(lis):``  ` `    ``# defining empty string as number``    ``number ``=` `""``    ` `    ``# convert the elements of list to string using type conversion``    ``for` `i ``in` `lis:``      ` `        ``# converting to string``        ``i ``=` `str``(i)``        ` `        ``# concat this to string``        ``number ``=` `number ``+` `i` `    ``# checking if it is palindrome``    ``if``(checkPalindrome(number)):``        ``return` `True``    ``else``:``        ``return` `False` `# Driver code``lis ``=` `[``1``, ``76``, ``39``, ``93``, ``67``, ``1``]` `if``(joinArray(lis)):``    ``print``(``"Palindrome"``)``else``:``    ``print``(``"not Palindrome"``)`

Output:

`Palindrome`

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