Comments on: Largest Palindromic Number In Python http://pthree.org/2007/09/15/largest-palindromic-number-in-python/ Linux. GNU. Freedom. Fri, 21 Nov 2008 03:53:18 +0000 http://wordpress.org/?v=2.7-beta3-9791 hourly 1 By: leed http://pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-108855 leed Sun, 26 Oct 2008 09:29:02 +0000 http://www.pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-108855 I think follow code is the fastest I have tried. maxnum = 0 for i in range(990, 99, -11): for j in range(999, i, -1): num = i * j if num <= maxnum: break else: strnum = str(num) if strnum == strnum[::-1]: maxnum = num break print maxnum I think follow code is the fastest I have tried.
maxnum = 0
for i in range(990, 99, -11):
for j in range(999, i, -1):
num = i * j
if num <= maxnum:
break
else:
strnum = str(num)
if strnum == strnum[::-1]:
maxnum = num
break
print maxnum

]]> By: i dont know http://pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-107970 i dont know Thu, 11 Sep 2008 15:50:14 +0000 http://www.pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-107970 what's are biggest 2 3-dgits palindrome? what’s are biggest 2 3-dgits palindrome?

]]> By: Athropos http://pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69317 Athropos Sun, 16 Sep 2007 12:52:44 +0000 http://www.pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69317 You should use the timeit module when you need to time something. It's better than using the time command because you then don't measure the startup time of the Python interpreter which can be a big part of the total time. <code> import timeit ... t1 = timeit.Timer('palindrome()', 'from __main__ import palindrome') print t1.timeit(20) </code> You should use the timeit module when you need to time something. It’s better than using the time command because you then don’t measure the startup time of the Python interpreter which can be a big part of the total time.

import timeit

...

t1 = timeit.Timer('palindrome()', 'from __main__ import palindrome')
print t1.timeit(20)

]]> By: phoenyx http://pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69305 phoenyx Sun, 16 Sep 2007 09:13:16 +0000 http://www.pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69305 FYI, it's considered bad form to post answers to problems outside of the forum. FYI, it’s considered bad form to post answers to problems outside of the forum.

]]> By: Duccio http://pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69298 Duccio Sun, 16 Sep 2007 07:38:38 +0000 http://www.pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69298 Good post...only a doubt. When you reach the column of the table of multiple of 11 (990,979,etc.) i think you must multiplicate this number for all the numbers smaller than this, and not only for multiple of 11 smaller than this. For example I don't see 990*989,990*988,etc. that are multiple of 11 too. Don't you think? Good post…only a doubt.
When you reach the column of the table of multiple of 11 (990,979,etc.) i think you must multiplicate this number for all the numbers smaller than this, and not only for multiple of 11 smaller than this. For example I don’t see 990*989,990*988,etc. that are multiple of 11 too. Don’t you think?

]]> By: Aaron http://pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69283 Aaron Sun, 16 Sep 2007 02:56:05 +0000 http://www.pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69283 @Peter- Ahh, yes. Good call. I've updated my post to reflect the change. @Seth- No problem. Let me know how far you get. :) @Peter- Ahh, yes. Good call. I’ve updated my post to reflect the change.

@Seth- No problem. Let me know how far you get. :)

]]> By: Seth http://pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69279 Seth Sun, 16 Sep 2007 02:23:25 +0000 http://www.pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69279 Never seen Project Euler before. Thanks for posting about it. :-) Never seen Project Euler before. Thanks for posting about it. :-)

]]> By: Peter http://pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69277 Peter Sun, 16 Sep 2007 02:06:38 +0000 http://www.pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69277 A few thoughts: - 5 digit palindromes are not necessarily divisible by 11, though that doesn't matter too much here as we're looking for 6 digit ones abcba = 10001a + 1010b + 100c - quick one liner (takes a few seconds here) <code>max([x*y for x in range(100,1000) for y in range(100,1000) if str(x*y)==str(x*y)[::-1]]) </code> A few thoughts:

- 5 digit palindromes are not necessarily divisible by 11, though that doesn’t matter too much here as we’re looking for 6 digit ones
abcba = 10001a + 1010b + 100c

- quick one liner (takes a few seconds here)

max([x*y for x in range(100,1000) for y in range(100,1000) if str(x*y)==str(x*y)[::-1]])

]]> By: Justin http://pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69256 Justin Sat, 15 Sep 2007 23:19:13 +0000 http://www.pthree.org/2007/09/15/largest-palindromic-number-in-python/#comment-69256 <code> def is_palin(num): s = str(num) return s == s[::-1] </code> 
def is_palin(num):
    s = str(num)
    return s == s[::-1]

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