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Python: Find all even palindromes up to n

Python Programming Puzzles: Exercise-45 with Solution

From Wikipedia,
A palindromic number (also known as a numeral palindrome or a numeric palindrome) is a number (such as 16461) that remains the same when its digits are reversed. In other words, it has reflectional symmetry across a vertical axis. The term palindromic is derived from palindrome, which refers to a word (such as rotor or racecar) whose spelling is unchanged when its letters are reversed. The first 30 palindromic numbers (in decimal) are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 202, ...

Write a Python program to find all even palindromes up to n.

Output:
Even palindromes up to 50 -
[0, 2, 4, 6, 8, 22, 44]

Even palindromes up to 100 -
[0, 2, 4, 6, 8, 22, 44, 66, 88]

Even palindromes up to 500 -
[0, 2, 4, 6, 8, 22, 44, 66, 88, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 404, 414, 424, 434, 444, 454, 464, 474, 484, 494]

Even palindromes up to 2000 -
[0, 2, 4, 6, 8, 22, 44, 66, 88, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 404, 414, 424, 434, 444, 454, 464, 474, 484, 494, 606, 616, 626, 636, 646, 656, 666, 676, 686, 696, 808, 818, 828, 838, 848, 858, 868, 878, 888, 898]

Sample Solution:

Python Code:

#License: https://bit.ly/3oLErEI

def test(n):
    return [i for i in range(0,n,2) if str(i) == str(i)[::-1]] 
n = 50
print("\nEven palindromes up to",n,"-")
print(test(n))
n = 100
print("\nEven palindromes up to",n,"-")
print(test(n))
n = 500
print("\nEven palindromes up to",n,"-")
print(test(n))
n = 2000
print("\nEven palindromes up to",n,"-")
print(test(n))

Sample Output:

Even palindromes up to 50 -
[0, 2, 4, 6, 8, 22, 44]

Even palindromes up to 100 -
[0, 2, 4, 6, 8, 22, 44, 66, 88]

Even palindromes up to 500 -
[0, 2, 4, 6, 8, 22, 44, 66, 88, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 404, 414, 424, 434, 444, 454, 464, 474, 484, 494]

Even palindromes up to 2000 -
[0, 2, 4, 6, 8, 22, 44, 66, 88, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 404, 414, 424, 434, 444, 454, 464, 474, 484, 494, 606, 616, 626, 636, 646, 656, 666, 676, 686, 696, 808, 818, 828, 838, 848, 858, 868, 878, 888, 898]

Flowchart:

Flowchart: Python - Find all even palindromes up to n.

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Python: Tips of the Day

Clamps num within the inclusive range specified by the boundary values x and y:

Example:

def tips_clamp_num(num,x,y):
  return max(min(num, max(x, y)), min(x, y))
print(tips_clamp_num(2, 4, 6))
print(tips_clamp_num(1, -1, -6))

Output:

4
-1