Creating a list within a list - not working

Question

Ok so I am having a problem whereby I need to make another list from a list I have already split. Here is the code.

def lists():
  instructionList = instructions()
  Lists = instructionList.split('\n')
  Instructions = []
  for values1 in Lists:
    Instructions = Instructions + [values1.split(",")]
    for values2 in Instructions:
      newLists = []
      newLists = newLists + [values2.split(" ")]
  print Instructions [3]

When I create the Instructions list it works, but when I try this further to create newLists it gives me this error=> The error was:'list' object has no attribute 'split' Attribute not found. You are trying to access a part of the object that doesn't exist.

I need to keep breaking the same list down. Also I am very new to this so please explain things carefully to me.

I'm not wanting to add values I am wanting to break the list down using xxx.split. But it won't continue letting me do it — Danrex, May 05 '13 at 19:44

score 1 · Answer 1 · answered May 05 '13 at 19:57

The problem is that values1.split(",") evaluates to a list, which you then put inside another list and append to Instructions. The variable Instructions then holds a list of lists. So, each element assigned to values2 will be of type list.

So, if your original instructions looks like: "a,b,c\nx,y,z\n"

Lists ends up looking like: ["a,b,c" , "x,y,z"]

Entering the outer loop, values1 first is: "a,b,c"

So, Instructions = Instructions + [values1.split(",")] gives: [ ["a" , "b" , "c"] ]

Then, when you go into the inner loop, values2 starts as: [ "a" , "b" , "c" ]

In other words, that's a list, which doesn't support split.

Beyond that, I'm actually not clear what you're trying to do with this code (what is the purpose of the inner loop?). If your goal is to get a list of lists, just remove that inner loop entirely. If you want one flat list, remove the square brackets around [values1.split(",") so that you're just appending two lists (and, again, remove that inner loop).

score -1 · Answer 2 · answered May 05 '13 at 19:44

-1

Because values2 is not a list it is a variable in Instructions! like Instructions[0] etc

answered May 05 '13 at 19:44

Aryan

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So why does values1 work then? I'm not questioning you just confused and I have no idea how to fix it? – Danrex May 05 '13 at 19:56

Creating a list within a list - not working

2 Answers2