How for loop works in python?

Question

I have a lists of lists in variable lists something like this:

[7, 6, 1, 8, 3]
[1, 7, 2, 4, 2]
[5, 6, 4, 2, 3]
[0, 3, 3, 1, 6]
[3, 5, 2, 14, 3]
[3, 11, 9, 1, 1]
[1, 10, 2, 3, 1]

When I write lists[1] I get vertically:

but when I loop it:

for i in list:
    print(i)

I get this horizontally.

7
6
1
8
3
etc...

So, how it works? How can I modify loop to go and give me all vertically?

How you say *When I write lists[1] I get vertically:*6 7 6 3 5 11 10? its impossible with the lists that you have provided! — Kasravnd
– Kasravnd, Commented Mar 1, 2015 at 21:34
And the for loop wouldn't give that output either. Please give real examples, and clarify what you're asking: What does "give me all vertically" mean exactly? — interjay
– interjay, Commented Mar 1, 2015 at 21:36

RomanK · Accepted Answer · 2015-03-01 21:33:58Z

4

Short answer:

for l in lists:
   print l[1]

answered Mar 1, 2015 at 21:33

RomanK

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2 Comments

user3136858 Over a year ago

Not sure, because index is out of range

RomanK Over a year ago

Can you elaborate? I'm using a collection iterator in the outer loop rather than a range. Of course, this assumes that all of your lists have at least two elements.

Kasravnd · Accepted Answer · 2015-03-01 21:39:00Z

1

Lists of lists

list_of_lists = [ [1, 2, 3], [4, 5, 6], [7, 8, 9]]
for list in list_of_lists:
    for x in list:
        print x

edited Mar 1, 2015 at 21:39

Kasravnd

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answered Mar 1, 2015 at 21:37

Theodor Straube

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1 Comment

user3136858 Over a year ago

I was trying that, it gave me rows, but I want columns.

heinst · Accepted Answer · 2015-03-01 21:50:24Z

0

Here is how you would print out the list of lists columns.

lists = [[7, 6, 1, 8, 3],
[1, 7, 2, 4, 2],
[5, 6, 4, 2, 3],
[0, 3, 3, 1, 6],
[3, 5, 2, 14, 3],
[3, 11, 9, 1, 1],
[1, 10, 2, 3, 1]]

for i in range(0, len(lists[1])):
    for j in range(0, len(lists)):
        print lists[j][i],
    print "\n"

answered Mar 1, 2015 at 21:50

heinst

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2 Comments

user3136858 Over a year ago

Yea, so close but I want loop all over the lists and get lists of columns. Not only first column.

heinst Over a year ago

@user3136858 can you be a little more specific? Example output? Ill modify my answer then to be exactly what you want

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