> I'm learning Python and I'm currently facing an issue with a small script I'm > writing. > > I need to generate a list of 30 numbers randomly chosen from 1, 2, 3, 4, 5 & > 6. However, I cannot have more than 2 numbers which are the same next to each > other. I came up with the following (Please ignore the fact that I'm trying > to avoid an IndexError in a stupid way :)):
Ok, we'll ignore that (for now ;-D). <snip /> > However, I wanted to look deeper in the above script and I created the > following: > > import random > iteraties = 5 > cijferreeks = 6 > aantal_cijfers = iteraties * cijferreeks > reeks = [] > while len(reeks) <= 1: > nummer = random.randrange(1, cijferreeks + 1, 1) > print 'Nummer: ', nummer > print 'Reeks: ', reeks > reeks.append(nummer) > print '\n' > > while len(reeks) <= aantal_cijfers: > nummer = random.randrange(1, cijferreeks + 1, 1) > print 'Nummer: ', nummer > print 'Voorlaatste vd reeks (-2): ', reeks[-2] > print 'Laatste vd reeks (-1): ', reeks[-1] > print 'Reeks: ', reeks > if nummer != reeks[-1] and nummer != reeks[-2]: > reeks.append(nummer) > else: > print 'Nummer: ', nummer, 'is gelijk aan vorige 2 nummers: ', reeks[-1], > '&', reeks[-2], '!' > print '\n' > print reeks > > When I run that, I can see there's something wrong with my if statement, it > triggers the else condition even when the 2 previous numbers in my list are > not the same... I'm not sure what is happening here... For an 'and' in a condition, only one part of the condition needs to be False for the condition to fail and skip to the else clause. Eg, with nummer=1, reeks[-1]=1 and reeks[-2]=2, it finds that 1 != 1 is False, and immediately skips to the else part. Ditto if nummer=2 and same reeks: first part is then True, but second part False, hence skip to else. I leave it up to you to find the correct if statement. (Hint: it's phrased in your third sentence at the top.) Btw, tip: always code in English. It just makes things easier for yourself when using other code examples, for example. But I just find generally good practice. Cheers, Evert _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
