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elements exchange
I met this in game section: arr = [4,3,1,2] arr[0], arr[arr[0]-1] = arr[arr[0]-1], arr[0] print(arr) but coldn’t understand why correct answer is [2,4,1,2] I guess this code changes or reassigns the 0-th and the 3-rd elements (4,2). How it connected with the 1-st element (3)?
3 Respuestas
+ 6
The trick for understand this is valutate first the right side of assignment.
Following your example:
arr[0], arr[arr[0]-1] = arr[arr[0]-1],arr[0]
and apply the "trick":
arr[0], arr[arr[0]-1] = arr[4-1],4
arr[0], arr[arr[0]-1] = 2,4
Then assign:
arr[0]= 2
arr[arr[0]-1]= arr[2-1]=
arr[1]= 4
Get the resulting array [2,4,1,2]
+ 4
KrOW thank’s. I understand my mistake: i thought that when assigne elements in one string it takes them in one moment (parallel). But it works consecutively like it was two separate strings with assignments. Right?
+ 2
Anna Starikova Yes, nothing happen in "parallel" in assignment. The imortant thing to remember is than its valuted FIRST the right side then assigned sequentially to left side.