How to pull a list out of an array in Python

Question

I need to pull an entire list out of an array. Essentially what I need my code to print the following.

a = [1, 2, 3]
b = [(1, 2, 3)]

if a != b
   print "a does not equal b"
else:
   print "a and b are the same!"

>>> a and b are the same!

Are you trying to test if both list are the same element-wise? — Christian Dean, Dec 11 '16 at 06:01
tried converting a into a tuple and comparing the two. tried to turn b into an array and compare the two. tried turning b into a tuple and comparing the two. I think i need to write a for loop that says if element 1 of a and b are the same and if element 2 of a and b are the same and if element 3 of a and b are the same then print that message but idk how to do that yet — Devin Liner, Dec 11 '16 at 06:09

score 1 · Answer 1 · answered Dec 11 '16 at 06:01

1

Just access the inner tuple and convert to list

a=[1,2,3]
b=[(1,2,3)]

bl = list(b[0])

print(a == bl) # True

answered Dec 11 '16 at 06:01

datawrestler

1,527
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2

This is a decent answer for *one* interpretation of a poorly written question. I don't see much point in responding to questions which are so unclear – John Coleman Dec 11 '16 at 06:04
i'm still new to python. still unclear about the differences between lists, arrays, and tuples. if a tuple is defined as lists inside of lists with the syntax ((),(),...) and an array is defined to have the syntax [], then i thought b was a list inside of an array. – Devin Liner Dec 11 '16 at 06:16
@DevinLiner No. `b` is a [tuple](https://docs.python.org/3.5/tutorial/datastructures.html#tuples-and-sequences) inside of a [list](https://docs.python.org/3.5/tutorial/datastructures.html#more-on-lists). – Christian Dean Dec 11 '16 at 06:17
@DevinLiner here is a pretty good discussion on the differences between lists and tuples http://stackoverflow.com/questions/626759/whats-the-difference-between-list-and-tuples – datawrestler Dec 11 '16 at 06:21
leaf gave me the answer – Devin Liner Dec 11 '16 at 06:25
see the answer i provided. – Devin Liner Dec 11 '16 at 06:30

score 0 · Answer 2 · edited Dec 11 '16 at 10:57

0

Converting it:

def con(st):
    res = []
    for x in st:
        res.append(x)
    return res

So the full code would be:

a = [1, 2, 3]
b = [(1, 2, 3)]
def con(st):
    res = []
    for x in st:
        res.append(x)
    return res
c = con(b[0])
if a != c:
   print "a does not equal b"
else:
   print "a and b are the same!"

edited Dec 11 '16 at 10:57

Peter Mortensen

30,738
21
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answered Dec 11 '16 at 06:05

ANVGJSENGRDG

153
1
8

Also you can use `list` instead of your `con` function. – Dan D. Dec 11 '16 at 06:12

score -1 · Accepted Answer · edited May 23 '17 at 12:16

-1

The user leaf gave me the answer.

a = [1, 2, 3]
b = [(1, 2, 3)]

if tuple(b[0]) != a:
   print "a does not equal b"
else:
   print "a and b are the same!"

Result >>> a and b are the same!

edited May 23 '17 at 12:16

Community

1
1

answered Dec 11 '16 at 06:26

Devin Liner

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How to pull a list out of an array in Python

3 Answers3