[Solved] Bubble sort function in Python

by 


for passnum in range(len(alist)-1,0,-1):

Per the range function documentation:

  • len(alist) - 1 is the length of the list (8) minus one (7). It represents some “starting” number.
  • 0 represents the “stopping” number.
  • -1 represents the “step” number.

These come together in range(len(alist) - 1, 0, -1) to say “count from 7 to 0, backwards – one negative step at a time”.

for i in range(passnum):

When range() is only passed one argument (a number), it counts from 0 to that number. The documentation gives this example:

list(range(10))  
# [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

So the code counts from 7 down to 0 – and every time it performs a single count, it immediately counts from 0 to that number.

solved Bubble sort function in Python