In short, I had an assignment problem where my final output should be a list of numbers, However in some cases, I have the good numbers in my list but just in the wrong order. I don't want to change my entire code since it is quite long. Thus, I was wondering if there is a trick, function or something that I can use where I can sort the list in a ascending manner however it doesn't put the negative numbers first.
For example, turn [0, -2, 1, -3, 2, -4, 3, -5, 4, -6] into [0, 1, -2, 2, -3, 3, -4, 4, -5, -6]
Another example, turn [0, 1, 5, 9, -2, 2, -5, -9, -1] into [0, -1, 1, -2, 2, -5, 5, -9, 9]
Another example, turn [12,-12] into [-12,12]
Here you can see that its sorted in an ascending manner but its start from 0 and not from a negative number.

CodePudding user response：

You can use the key parameter of sorted with a tuple of the absolute value and the value itself. This will thus sort by the absolute and in case of tie, put the negative number first.

out = sorted(your_lst, key=lambda x: (abs(x), x))

Output on the first example:

[0, 1, -2, 2, -3, 3, -4, 4, -5, -6]

If you want to sort in place:

your_lst.sort(key=lambda x: (abs(x), x))

CodePudding user response：

You can use:

lst = [0, -2, 1, -3, 2, -4, 3, -5, 4, -6]
print(sorted(lst, key=lambda x: (abs(x), x)))

output

[0, 1, -2, 2, -3, 3, -4, 4, -5, -6]

Basically you sort the items based on two priorities: first the absolute value of the numbers so that 2 and -2 come next to each other. Also you mentioned, you want -2 to come before 2. The second item of the tuple does this. You are actually comparing tuples. First items are equal so comparison continues to the second items(ascending order):

lst = [(2, 2), (2, -2)]
print(sorted(lst)) # [(2, -2), (2, 2)]