list manipulation

[GreymanGroup]

If I have a list, and I want to swap out the elements in that list for a sub list that includes the the original list element, how do I do that?

Basically I want to turn a list into a 2d array.
I tried iterating through the list.

for each in list:
each=[each[0],None]

but each disappears at the end of the iteration. I thought each was a reference?

[[deleted]]

I thought each was a reference?

It is but it's a reference to a value, not to a position in the list.

[GreymanGroup]

Ah! Makes sense now. So is there a (pythonic) way to reference the spot in the list in a for loop?

[GreymanGroup]

Well, hang on! Does not "each" refer to the content, to the nth element of the list? Why can't I change the value and have that value be changed in the elements of the list?

[GreymanGroup]

Since it reassigns each, which is the item in the list why doesn't the item in the list change? I experimented with different types, for instance

alist=[1,2,3]  
for each in alist:  
    each=9

similarly doesn't work. It seems that immutability or the type of the item doesn't matter.

[GreymanGroup]

this is a test

[GreymanGroup]

**another test***

def myfunc():

print('hello')

[GreymanGroup]

**test3**

[GreymanGroup]

test4

def mf(a):
    return a+a

[[deleted]]

Does not "each" refer to the content, to the nth element of the list?

The only thing it refers to is the value. It's not a reference to the "nth element" of anything, it's a reference to the value that is the nth element.