On 02/23/2018 06:40 AM, Peter Otten wrote: > vinod bhaskaran wrote: > >> Hi All, >> >> I am a beginner programmer and i wrote a small program (as per a >> assignment i saw) as below: >> >> newlist = [] >> for a in range(2,5): >> for b in range (0,3): >> newlist.append([a]) >> a = a + 1 >> print(newlist) >> >> it gives the expected output as below: >> [[2], [3], [4], [3], [4], [5], [4], [5], [6]] >> >> but when i try list comprehension i am not able to get it correct....can >> someone please suggest where the (a=a+1) should be placed in a list >> comprehension > > You canot sneak a statement like > >> a = a + 1
I would go further: you should not be sneaking it into your original code either - it's not a great idea to modify the iteration variable while inside the loop. It works this time because you're iterating over a list that has been made for you by range: >>> print(range(2,5)) [2, 3, 4] so second time through 'a' gets the second value in the list and it doesn't break things that you changed 'a' while it was in use, but it's a bad habit to get into - if you use the same concept in a while loop, say, you will get unpleasant surprises. So to further Peter's suggestion - try to figure out how to stop doing that in your inner loop, and it will be much more clear what to do in the comprehension form. _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
