replace one list with another list in python in the same array

Question

i can always change bwtween list if I do not have them in One array...

If I have an array having more than one list

 a = [[2,3,4,],[8,14,13],[12,54,98]]

how do I replace a[2] with a[0] ??

Thanks in Advance

Answer 1

Lists are mutable so you probably want to replace list items, not the lists themselves:

a[2][:] = a[0]

If you want to swap lists rather than replace them then:

a[0], a[2] = a[2], a[0]

Answer 2

For your original post:

 
 
 
 
  
  
  a = [[2,3,4,],[8,14,13],[12,54,98]] a[2] = a[0]
 
 
  

then a will be:

 
 
 
 
  
  
  [[2, 3, 4], [8, 14, 13], [2, 3, 4]]
 
 
  

Update based on comment to sdolan below:

If you want to exchange the two, you could simply do this:

[[12, 54, 98], [8, 14, 13], [2, 3, 4]]

giving

 [[12, 54, 98], [8, 14, 13], [2, 3, 4]] 

Answer 3

You can just assign it:

>>> a = [[2,3,4,],[8,14,13],[12,54,98]]
>>> 
>>> a[2] = list(a[0]) # list() to create a new copy
>>> a
[[2, 3, 4], [8, 14, 13], [2, 3, 4]]

Answer 4

The way you asked this is to just change the array from a = [[2,3,4,],[8,14,13],[12,54,98]] to a = [[2,3,4,],[8,14,13],[2,3,4,]]

so you can do a[2] = a[0]

but if you want to swap them, you will need something like:

b = a[0]
a[0] = a[2]
a[2] = b

EDIT for shorthand:

a[0], a[2] = a[2], a[0]