python - Why the results are different from using merge(lista+listb) -

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• (python) adding list without brackets 3 answers

here i'm trying merge 2 lists, making 1 whit items.

n = [[1, 2, 3], [4, 5, 6, 7, 8, 9]]  def flatten(n):     s=[]     x in n:         s.append(x)     return s  print flatten(n) 

i'm trying have result

[1,2,3,4,5,6,7,8,9]  

but i'm getting

[[1, 2, 3], [4, 5, 6, 7, 8, 9]] 

i dont understand why, think i'm assigning each value list 's' in loop.

you're appending list. each sublist appended new list own item, way originally. want extend list instead:

s.extend(x)