Why the value in list stay the same?

Question

Does lambda not change value when using key= in sort() function?

nas = [1,2,3,4,5]

nas.sort(key=lambda a: a + 1)
print(nas) 

nas still has same value why didn't get 1 added using lambda?

Answer 1

As the name might suggest, sort only... sorts . It won't change any of the elements from the lambda you provide it. That lambda is only used to define how elements of your list should be sorted.

So for example, when trying to compare 3 and 4 , your lambda instructs it to compare 3 as if it were 4 , and 4 as if it were 5 . Of course, this would have the same impact of just comparing the integers directly:

nas = [1,2,3,4,5]

nas.sort(key=lambda a: a + 1) # Or just `nas.sort()`
print(nas)